HAZARDOUS WASTE CHARACTERISTICS

SCOPING STUDY

U.S. Environmental Protection Agency

Office of Solid Waste

November 15, 1996
i

TABLE OF CONTENTS

Page

EXECUTIVE SUMMARY ................................................................... ES-1

CHAPTER 1. INTRODUCTION ............................................................ 1-1

1.1 Purpose and Requirements of the Hazardous Waste Characteristics Scoping Study . . 1-1

1.2 Regulatory Background ................................................. 1-2

1.3 Approach for Studying Potential Gaps in the Hazardous Waste Characteristics ..... 1-4

Step 1: Characterize Releases from Non-Hazardous Industrial Waste Management . 1-4

Step 2: Categorize Risks Associated with Non-Hazardous Industrial Waste Management 1-4

Step 3: Review the Existing Characteristics ................................ 1-4

Step 4: Identify Gaps Associated with Non-TC Chemicals .................... 1-6

Step 5: Identify Potential Gaps Associated with Certain Natural Resource Damages and

Large-Scale Environmental Problems ............................... 1-6

Step 6: Review State Expansions of TC and State Listings .................... 1-7

Step 7: Evaluate the Industries and Waste Management Practices Associated with

Potential Gaps ................................................. 1-7

Step 8: Assess Regulatory Programs' Coverage of Potential Gaps ............... 1-8

Step 9: Present Integrated Evaluation of Nature and Extent of Potential Gaps ..... 1-8

1.4 Report Outline ........................................................ 1-8

CHAPTER 2. RELEASES FROM NON-HAZARDOUS INDUSTRIAL WASTE MANAGEMENT UNITS 2-1

2.1 Methodology .......................................................... 2-1

2.1.1 Criteria For Selecting Releases .................................... 2-1

2.1.2 Approach For Identifying Releases ................................. 2-3

2.1.2.1 State Industrial D Programs ................................ 2-3

2.1.2.2 State Superfund Programs ................................. 2-5

2.1.2.3 Federal Superfund Program ................................ 2-6

2.1.2.4 Construction and Demolition (C&D) Landfill Report ............ 2-6

2.1.3 Release Profile Preparation ....................................... 2-7

2.2 Results ............................................................... 2-8

2.2.1 Number of Cases By State ........................................ 2-8

2.2.2 Number of Cases By Industry ..................................... 2-10

2.2.3 Number of Cases By Type of Waste Management Unit ................. 2-11
TABLE OF CONTENTS (Continued)

Page

ii

2.2.4 Type of Media Affected .......................................... 2-12

2.2.5 Types of Contaminants Released ................................... 2-13

2.3 Major Limitations ...................................................... 2-17

CHAPTER 3. POTENTIAL GAPS ASSOCIATED WITH HAZARDOUS WASTE CHARACTERISTICS DEFINITIONS 3-1

3.1 Types of Risks Addressed by RCRA Hazardous Waste Characteristics ............ 3-1

3.1.1 Statutory and Regulatory Framework ............................... 3-1

3.1.2 Risks Associated with Physical Hazards ............................. 3-3

3.1.3 Acute Toxic Hazards to Humans ................................... 3-4

3.1.4 Chronic Toxicity Risks to Humans ................................. 3-4

3.1.5 Risks to Non-Human Receptors ................................... 3-5

3.1.6 Other Risks Associated with Non-Hazardous Industrial Waste Management 3-6

3.2 Ignitability Characteristic ................................................ 3-8

3.2.1 Definition of Ignitability ......................................... 3-8

3.2.2 Potential Gaps Related to Definition of Ignitability .................... 3-9

3.2.3 Potential Gaps Related to Ignitability Test Methods ...................... 3-12

3.3 Corrosivity ........................................................... 3-12

3.3.1 Definition of Corrosivity ......................................... 3-12

3.3.2 Potential Gaps Related to Definition of Corrosivity .................... 3-13

3.3.3 Potential Gaps Related to Corrosivity Test Methods ................... 3-16

3.4 Reactivity ............................................................ 3-16

3.4.1 Definition of Reactivity .......................................... 3-16

3.4.2 Potential Gaps Related to Definition of Reactivity ..................... 3-17

3.4.3 Potential Gaps Related to Reactivity Test Methods .................... 3-19
TABLE OF CONTENTS (Continued)

Page

iii

3.5 Potential Gaps Associated with the Toxicity Characteristic ..................... 3-19

3.5.1 Definition of Toxicity Characteristic ................................ 3-19

3.5.2 Changes in Groundwater Pathway Analysis .......................... 3-21

3.5.3 Potential Inhalation Pathway Risks Associated with TC Analytes ......... 3-27

3.5.4 Potential Risks from Surface Water Exposures ....................... 3-33

3.5.5 Potential Indirect Pathway Risks from TC Analytes .................... 3-35

3.5.6 Potential for Acute Adverse Effects of Exposures to TC Analytes ......... 3-38

3.5.7 Potential Risks to Ecological Receptors from TC Analytes .............. 3-38

3.6 Potential Gaps Associated with TCLP ...................................... 3-39

3.6.1 TCLP Background .............................................. 3-39

3.6.2 Limitations of the TCLP ......................................... 3-42

CHAPTER 4. POTENTIAL GAPS ASSOCIATED WITH NON-TC CHEMICALS ................ 4-1

4.1 Overview of Methodology ............................................... 4-1

Step 1: Identify and Classify Known Non-Hazardous Industrial Waste Constituents . 4-1

Step 2: Identify and Screen Possible Non-Hazardous Industrial Waste Constituents . 4-1

Step 3: Apply Hazard-Based Screening Criteria ............................. 4-3

Step 4: Review Relevant Multipathway Risk Modeling Results ................. 4-3

Step 5: Identify Potential Acute Hazards .................................... 4-3

Step 6: Summarize Findings ............................................. 4-3

4.2 Identify and Classify Known Constituents of Non-Hazardous Industrial Wastes ..... 4-3

4.3 Identify Possible Non-Hazardous Industrial Waste Constituents of Potential Concern 4-7

4.3.1 Approach to Identifying Potentially Hazardous Chemicals .............. 4-7

4.3.2 Screening Approach ............................................ 4-9

4.3.3 Toxicity, Fate, and Transport Screening for Possible Non-Hazardous Industrial

Waste Constituents ............................................. 4-12
TABLE OF CONTENTS (Continued)

Page

iv

4.3.4 Release Volume Screening of Possible Non-Hazardous Industrial Waste

Constituents ................................................... 4-15

4.3.5 Summary of Possible Non-Hazardous Industrial Waste Constituents ...... 4-20

4.4 Combine and Screen Known and Possible Non-Hazardous Industrial Waste Constituents 4-20

4.4.1 Combine the Lists .............................................. 4-20

4.4.2 Screen Combined List Against Single Criteria ........................ 4-25

4.4.3 Screen Combined List Against Multiple Parameters ................... 4-33

4.5 Driving Risk Pathways for the Known and Possible Non-Hazardous Industrial Waste

Constituents .......................................................... 4-34

4.6 Potential Acute Hazards Associated With Known and Possible Non-Hazardous Industrial

Waste Constituents ..................................................... 4-35

4.7 Identify Individual Chemicals and Classes of Chemicals Constituting Potential Gaps . 4-40

CHAPTER 5. POTENTIAL GAPS ASSOCIATED WITH NATURAL RESOURCE DAMAGES AND LARGE-SCALE ENVI

PROBLEMS ................................................................ 5-1

5.1 Damage to Groundwater Resources ........................................ 5-1

5.2 Damage to Local Air Quality from Odors ................................... 5-2

5.3 Large-Scale Environmental Problems ...................................... 5-4

5.3.1 Air Deposition to the Great Waters ................................. 5-4

5.3.2 Airborne Particulates ............................................ 5-6

5.3.3 Global Climate Change .......................................... 5-7

5.3.4 Potential Damages from Endocrine Disruptors ........................ 5-9

5.3.5 Red Tides ..................................................... 5-13

5.3.6 Stratospheric Ozone Depletion .................................... 5-14

5.3.7 Tropospheric Ozone and Photochemical Air Pollution ................. 5-15

5.3.8 Water Pollution ................................................ 5-15

CHAPTER 6. STATE EXPANSIONS OF THE TOXICITY CHARACTERISTIC AND LISTINGS . . 6-1

6.1 State Expanded Toxicity Characteristics .................................... 6-1

6.2 State Only Listings ..................................................... 6-2

6.3 State Restrictions on Exemptions .......................................... 6-5

6.4 Summary ............................................................. 6-6
TABLE OF CONTENTS (Continued)

Page

v

CHAPTER 7. SUMMARY OF POTENTIAL GAPS ........................................... 7-1

7.1 Organization of the Analysis of Potential Gaps ............................... 7-1

7.2 Summary of Potential Gaps .............................................. 7-2

CHAPTER 8. POTENTIAL GAPS AS FUNCTION OF INDUSTRY AND WASTE MANAGEMENT METHODS 8-1

8.1 Data Sources and Major Limitations ....................................... 8-1

8.2 Potential Gaps as a Function of Industry/Waste Source ......................... 8-3

8.2.1 Non-Hazardous Industrial Waste Generation by Industry ............... 8-3

8.2.2 Industries Responsible for Documented Non-Hazardous Industrial Waste Releases 8-5

8.2.3 Occurrence of High-Hazard Industrial Waste Constituents by Industry ..... 8-8

8.2.4 Industries Reporting Releases of TC Analytes or Known or Possible NonHazardous Industrial Waste Constituents ............................ 8-18

8.3 Potential Gaps as a Function of Management Practices ......................... 8-21

8.3.1 Waste Management Practices by Waste Type and Industry .............. 8-21

8.3.2 Management Practices Seen in the Release Descriptions ................ 8-24

8.3.3 Potential Hazards Associated with Use Constituting Disposal ............ 8-29

8.3.4 Potential Hazards Associated with Other Management Practices ......... 8-31

CHAPTER 9. POTENTIAL FOR GAPS TO BE ADDRESSED BY EXISTING REGULATIONS .... 9-1

9.1 RCRA Programs ....................................................... 9-1

9.1.1 Hazardous Waste Programs ......................................... 9-1

9.1.2 Subtitle D ....................................................... 9-3

9.2 Medium-Specific Regulations ............................................ 9-3

9.2.1 Clean Water Act .................................................. 9-4

9.2.2 Safe Drinking Water Act ........................................... 9-7

9.2.3 Clean Air Act Amendments ......................................... 9-10

9.3 Federal Insecticide, Fungicide, and Rodenticide Act ........................... 9-13

9.4 Toxic Substance Control Act ............................................. 9-15

9.5 Pollution Prevention .................................................... 9-15

9.6 Occupational Safety and Health Act ........................................ 9-16
TABLE OF CONTENTS (Continued)

Page

vi

9.7 Hazardous Materials Transportation Act .................................... 9-16

9.8 Summary ............................................................. 9-19

CHAPTER 10. SUMMARY EVALUATION OF NATURE AND EXTENT OF POTENTIAL GAPS . . 10-1

10.1 Overview of the Evaluation of Potential Gaps ................................ 10-1

10.1.1 Objectives of the Gaps Analysis ................................... 10-1

10.1.2 Criteria Used for Evaluating Gaps ................................. 10-1

10.2 Findings of the Evaluation ............................................... 10-3

10.2.1 Potential Gaps Associated with the ICR Characteristics ................ 10-3

10.2.2 Potential Gaps Associated with TC Analytes ......................... 10-8

10.2.3 Potential Gaps Associated with Non-TC Waste Constituents ............ 10-14

10.2.4 Potential Gaps Associated With Resource Damage and Large-Scale Environmental

Problems ..................................................... 10-22

10.2.5 Gaps Associated with State TC Expansions and Listings ................. 10-25

10.2.6 Major Data Gaps and Uncertainties .................................. 10-26

10.3 Framework for Determining an Appropriate Course of Action ................... 10-27

10.3.1 Step 1: Identify Critical Research Needs and Next Steps Necessary to Analyze

Key Issues and Fill Major Data Deficiencies ......................... 10-27

10.3.2 Step 2: Identify and Evaluate Options to Address Any Clearly Identified Gaps10-27
vii

LIST OF EXHIBITS

Page

Exhibit 1-1 Scoping Study Approach ........................................................ 1-5

Exhibit 2-1 Number of Release Descriptions By State .......................................... 2-9

Exhibit 2-2 Number of Management Units & Volume of Waste Managed On-Site, by State (1985) ...... 2-9

Exhibit 2-3 Number of Case Studies by Industry (SIC) .......................................... 2-10

Exhibit 2-4 Number of Case Studies By Waste Management Unit ................................. 2-12

Exhibit 2-5 TC Contaminants Detected in Case Studies ......................................... 2-14

Exhibit 2-6 Contaminants with SMCLs Detected in Case Studies ................................. 2-15

Exhibit 2-7 Other Contaminants Detected in At Least Three Case Studies ........................... 2-16

Exhibit 2-8 Most Common Constituents By Industry ............................................ 2-18

Exhibit 3-1 Risks Potentially Associated with Non-Hazardous Industrial Waste Management ........... 3-7

Exhibit 3-2 Materials Formerly Classified by DOT as Combustible Liquids (which generally are not

RCRA ignitable) .............................................................. 3-11

Exhibit 3-3 Other Definitions of Reactivity ................................................... 3-18

Exhibit 3-4 TC Constituents and Regulatory Levels (mg/l) ....................................... 3-20

Exhibit 3-5 Comparison of TC Regulatory Concentrations and HWIR-Waste Proposed Exit/Leech Levels . 3-25

Exhibit 3-6 Summary of Inhalation Pathway Screening Methods, Input Data, and Models Used for

Bounding Risk Analysis ........................................................ 3-29

Exhibit 3-7 Emission Fraction for Air Releases of Volatile TC Analytes ............................ 3-30

Exhibit 3-8 Inhalation Pathway Risks for TC Analytes and Their Dependence on Fate and Transport

Properties .................................................................... 3-32

Exhibit 3-9 Major Fate and Transport Parameters for TC Analytes ................................ 3-36

Exhibit 3-10 Ratios of TC Leachate Regulatory Levels to Ambient Water Quality Criteria for Aquatic

Life ......................................................................... 3-40

Exhibit 4-1 Flow Chart of Procedures Used to Identify Non-TC Chemicals Posing Potential Gaps in the

TC Characteristics ............................................................. 4-2

Exhibit 4-2 Known Non-Hazardous Industrial Waste Constituents Found in Case Studies, ISDB, Listings

Documents, and Effluent Guidelines by Chemical Class ............................... 4-6

Exhibit 4-3 Lists Used to Identify Possible Non-Hazardous Industrial Waste Constituents .............. 4-8

Exhibit 4-4 Criteria Considered for Screening Non-Hazardous Industrial Waste Constituents ........... 4-10

Exhibit 4-5 Toxicity Screening Results for Possible Non-Hazardous Industrial Waste Constituents ....... 4-13

Exhibit 4-6 Persistence and Bioconcentration/Bioaccumulation Screening Results for Possible NonHazardous Industrial Waste Constituents ........................................... 4-16

Exhibit 4-7 Screening of High-Toxicity, Persistent, Bioaccumulative/Bioconcentrating Possible NonHazardous Industrial Waste Constituents Against TRI Release Volumes .................. 4-17

Exhibit 4-8 Possible Non-Hazardous Industrial Waste
LIST OF EXHIBITS (Continued)

Page

viii

Constituents by Chemical Class .................................................. 4-21

Exhibit 4-9 Screening of Known Non-Hazardous Industrial Waste Constituents Against TRI Release

Volumes ..................................................................... 4-22

Exhibit 4-10 Toxicity Summary of Known and Possible Non-Hazardous Industrial Waste Constituents .... 4-26

Exhibit 4-11 Potential Endocrine Disruptors ................................................... 4-27

Exhibit 4-12 TRI Releases and Non-Confidential TSCA Production Volume Data for the Known and Possible NonHazardous Industrial Waste Constituents ........................................... 4-28

Exhibit 4-13 Volatility, Persistence, and Bioaccumulation/Bioconcentration Summary Potential of Known and

Possible Non-Hazardous Industrial Waste Constituents ................................ 4-29

Exhibit 4-14 LNAPL/DNAPL Formation Potential of Known and Possible Non-Hazardous Industrial Waste

Constituents .................................................................. 4-32

Exhibit 4-15 Multiple Screening Criteria Applied to Known and Possible Non-Hazardous Industrial Waste

Constituents .................................................................. 4-34

Exhibit 4-16 Lowest Proposed HWIR-Waste Exit Levels for Known and Possible Non-Hazardous Industrial

Waste Constituents ............................................................ 4-36

Exhibit 4-17 Potential Acute Hazards Associated with Known and Possible Non-Hazardous Industrial

Waste Constituents ............................................................ 4-39

Exhibit 4-18 Potential Gaps in the Hazardous Waste Characteristics Identified Based on the Hazardous

Properties of Known and Possible Non-Hazardous Industrial Waste Constituents ........... 4-41

Exhibit 5-1 Constituents/Properties with SMCLs Found in Release Descriptions ..................... 5-2

Exhibit 5-2 Chemicals from Release Descriptions with Low Odor Thresholds ....................... 5-3

Exhibit 5-3 Initial List of Large-Scale Environmental Problems ................................... 5-4

Exhibit 5-4 U.S. Sources of Air Pollutants of Concern for Great Waters ............................ 5-5

Exhibit 6-1 State Toxicity Characteristics: Additional Constituents and More Stringent Regulatory

Levels ....................................................................... 6-3

Exhibit 6-2 State Toxicity Criteria Applied to Whole Waste (Representative Sample) ................. 6-4

Exhibit 7-1 Summary of Potential Gaps in the Hazardous Waste Characteristics ...................... 7-2
LIST OF EXHIBITS (Continued)

Page

ix

Exhibit 8-1 Estimated Generation of Non-Hazardous Industrial Waste by Major Industry Group ......... 8-4

Exhibit 8-2 Chemicals Exceeding Health-Based and Non-Health-Based Regulatory Levels in the Release

Descriptions for Non-Hazardous Waste Management ................................. 8-6

Exhibit 8-3 Numbers of Chemical Detections and Frequencies of Regulatory Exceedences in Release

Descriptions .................................................................. 8-7

Exhibit 8-4 Most Frequently Occurring Constituents in the Release Descriptions ..................... 8-9

Exhibit 8-5 Occurrence of Waste Constituents by Industry Group ................................. 8-11

Exhibit 8-6 Non-Hazardous Industrial Waste Constituents Reported Released by Industry .............. 8-19

Exhibit 8-7 Volume of Non-Hazardous Industrial Waste Managed in Land-Based Facilities in 1985 ..... 8-22

Exhibit 8-8 Active Non-Hazardous Industrial Waste Management Units in 1985 by Major Industry Group 8-23

Exhibit 8-9 Non-Hazardous Industrial Waste Management by Industry and Waste Type from TSDR and ISDB 8-25

Exhibit 8-10 Waste Management Unit Types in the Release Descriptions ............................ 8-30

Exhibit 9-1 TC Constituents with Effluent Limits Established under CWA .......................... 9-5

Exhibit 9-2 CWA Effluent Limitations Relevant to Certain Known Non-Hazardous Industrial Waste

Constituents .................................................................. 9-6

Exhibit 9-3 CWA Coverage of Industries Represented in Release Descriptions ...................... 9-7

Exhibit 9-4 TC Constituents with SDWA MCL Levels .......................................... 9-8

Exhibit 9-5 MCLs for Known Non-Hazardous Industrial Waste Constituents of Concern in Groundwater

Pathways .................................................................... 9-9

Exhibit 9-6 TC Constituents Designated as HAPs under CAA .................................... 9-11

Exhibit 9-7 CAA Hazardous Air Pollutants (HAPs) Specified for Potential Gap Constituents ........... 9-12

Exhibit 9-8 CAA Coverage of Industries Represented in Release Descriptions ....................... 9-13

Exhibit 9-9 Status of Pesticides That are TC Analytes or Known Non-Hazardous Industrial Waste

Constituents .................................................................. 9-14

Exhibit 9-10 TC Constituents with Established OSHA PELs ...................................... 9-17

Exhibit 9-11 OSHA PELs Specified for Known Non-Hazardous Industrial Waste Constituents ........... 9-18

Exhibit 9-12 Potential Gaps and Potential Non-RCRA Regulatory Control ........................... 9-19
LIST OF EXHIBITS (Continued)

Page

x

Exhibit 10-1 Evaluation of Potential Gaps Associated With the Ignitability, Corrosivity, and Reactivity (ICR)

Characteristics ................................................................ 10-4

Exhibit 10-2 Evaluation of Potential Gaps Associated with Toxicity Characteristic Analytes and TCLP .... 10-9

Exhibit 10-3 Evaluation of Potential Gaps Associated with Non-TC Chemicals ....................... 10-15

Exhibit 10-4 Evaluation of Potential Gaps Associated With Certain Large-Scale Environmental Problems . . 10-24
HAZARDOUS WASTE CHARACTERISTICS

SCOPING STUDY:

EXECUTIVE SUMMARY

U.S. Environmental Protection Agency

Office of Solid Waste

November 15, 1996
Page ES-1

EXECUTIVE SUMMARY

The U.S. Environmental Protection Agency (EPA), Office of Solid Waste has

investigated potential gaps in the current hazardous waste characteristics promulgated under the

federal Resource Conservation and Recovery Act (RCRA). This report, the Hazardous Waste

Characteristics Scoping Study, presents the findings of that investigation.

THE SCOPING STUDY: AN EARLY STEP

This study is a first step for the Agency in fulfilling a long-standing goal to review the

adequacy and appropriateness of the hazardous characteristics. The study also fulfills an

obligation in a consent decree with the Environmental Defense Fund (EDF).

The study is by design a scoping study and, therefore, does not conclusively identify

particular chemical classes for regulation, or fundamental flaws in the overall regulatory

framework requiring immediate regulatory action. However, the study does identify several key

areas that merit further analysis due to the significant potential for improving hazardous waste

management practices and protection to health and the environment. Thus, the scoping study

provides a catalogue of potential gaps in the hazardous waste characteristics.

The Agency considers that this study is one very critical component of a broader array of

efforts underway to review and improve the RCRA program, to ensure that regulation is

appropriate to the degree of risk posed by hazardous wastes and waste management practices. 

Efforts involve both regulatory and de-regulatory actions, as appropriate for specific wastes and

waste management practices.

STUDY PROCESS AND FINDINGS

Review of Current Characteristics

The review of the current characteristic regulations evaluated the protectiveness of the

characteristics against the risks they were intended to address and also risks they were not

specifically intended to address. For example, EPA evaluated risks that are now addressed by

the Toxicity Characteristic (TC), e.g., direct ingestion of groundwater, by considering new

groundwater modeling techniques that have been in use since the promulgation of the current TC

levels, as well as any changes to the toxicity values on which the original levels were based. In

addition, EPA evaluated risks from other exposure pathways and to ecological receptors, which

are both risks not intended to be protected by the original TC.

The review of the current TC regulatory levels suggests that: (1) further analysis of

the current TC regulatory levels should be conducted using new groundwater modeling

techniques, as well as considering changes to toxicity values for specific constituents; and

(2) non-groundwater pathways and ecological receptors--not currently addressed by TC

provisions--may be of potential concern. The study included some screening analyses of
Page ES-2

potential air releases from surface impoundments and land application units. The Agency found

that inhalation risk levels for a significant number of current TC constituents at the fenceline

(under certain exposure conditions) exceeded the allowable risk levels upon which the TC is

based.

Waste piles and land application units may be of special concern for ecological

receptors due to surface runoff. Thirteen TC constituents have regulatory levels that are

10,000 or more times higher than Ambient Water Quality Criteria concentrations, with four of

these being at least 100,000 times higher, suggesting that the level of protectiveness of the TC

may not be very high for ecological receptors.

The study also identifies the need to examine a broader array of leaching

procedures, in addition to the Toxicity Characteristic Leaching Procedure (TCLP), to

better predict environmental releases from various waste types and waste management

conditions. Notable examples are the inability of the TCLP to predict significant releases under

highly alkaline conditions or to media other than groundwater, or to serve as a leaching

procedure for oily wastes.

The most obvious potential gap identified for the ignitability and reactivity

characteristics is the reference to outdated DOT regulations. Other potential gaps identified

for these characteristics include the exclusion of combustible liquids and lack of specific test

methods for non-liquids for ignitability; exclusion of corrosive solids, not addressing corrosion

of non-steel materials and solubilization of non-metals, and whether pH limits are adequately

protective for corrosivity; and, an overly-broad definition and lack of specific test methods for

reactivity.

Releases from Non-Hazardous Industrial Waste Facilities

The Agency identified actual releases of non-hazardous waste constituents as one means

of finding potential problem constituents and management activities. EPA reviewed data on

non-hazardous industrial waste management activities that was readily available from state

monitoring and compliance files. The Agency focused on wastes that are not currently regulated

as hazardous (by virtue of being listed or exhibiting a characteristic) to identify releases

potentially causing human health or environmental damages.

The Agency considered three major factors in judging whether a release was an

appropriate case study for this evaluation. A release had to meet all three of the following

criteria to be included: (1) The source of contamination had to be a waste management unit or

other intended final disposal area that received only non-hazardous industrial waste; (2) A

release from a waste management unit must have caused contamination at levels of potential

concern (constituent-specific concentrations that exceed federal standards or state guidelines or

regulations); and, (3) Documented evidence must be available to support the exceedences

referred to in (2).

EPA found 112 environmental release case studies in 12 states with readily available

(and not necessarily representative) data on non-hazardous waste management units. The
Page ES-3

releases were found from facilities in 15 (2-digit) Standard Industry Classification (SIC)

industries. The top four categories were: SIC 49: Electric, Gas, and Sanitary Services (refuseside only); SIC 26: Paper & Allied Products; SIC 28: Chemical & Allied Products; and, SIC

20: Food & Kindred Products.

Over 90 percent of the releases were from landfills or surface impoundments and

nearly all (98 percent) involved groundwater contamination. This is most likely because

groundwater monitoring is the most common method for detecting releases from waste

management units.

Many of the chemical constituents most commonly detected above a regulatory level

are already addressed in the current TC, even though the release occurred from nonhazardous waste management. The 20 constituents most commonly detected above a

regulatory level are inorganics. The constituents that exceeded state groundwater protection

standards or health-based federal drinking water standards most frequently were lead,

chromium, cadmium, benzene, arsenic and nitrates. All of these, with the exception of nitrates,

are current TC constituents. Organic constituents, both TC and non-TC, were also identified in

the case studies, however, they were detected less frequently than the inorganic toxicity

characteristic constituents.

 This collection of release descriptions is not statistically representative of problem

industries nor intended to identify particular problem facilities. The Agency believes that

the case studies are indicative of the type of releases associated with the management of nonhazardous wastes in the types of facilities identified. The Agency also believes that information

on releases from past waste management practices is useful in demonstrating the potential for

human health or environmental damage.

Non-TC Chemical Constituents

In reviewing chemicals and chemical classes not currently regulated by the TC,

EPA found in excess of 100 constituents that potentially occur in waste and may pose

significant risks. EPA reviewed 37 regulatory or advisory lists of chemicals to identify possible

constituents of non-hazardous wastes. EPA also compiled a list of chemicals which are “known”

to be constituents of non-hazardous wastes because they were identified in the environmental

release case studies or other Agency data sources on non-hazardous industrial wastes. EPA

screened these chemicals and narrowed the list to possible constituents of non-hazardous waste

that, by virtue of their toxicity, fate and transport properties, or exposure potential, could pose

significant risks to human health and/or the environment.

These chemicals were both inorganics and organics, and include volatiles, nonvolatile organics, PAHs and pesticides. Because of the large number of constituents identified

as candidates and the limited time available for the scoping study, no risk analyses were

conducted. However, it may be a reasonable next step to assess the potential risks for a subset of

these constituents.
Page ES-4

Natural Resource Damages/Large-Scale Environmental Problems

The Agency examined the potential for broad environmental impacts from nonhazardous waste management. These impacts may include damages to natural resources

which diminish the value and usability of a resource without threatening human health, as well

as possible contributions to regional and global environmental problems.

With respect to groundwater contamination, over 80 percent of the facilities

identified in the case studies discussed earlier had releases exceeding secondary drinking

water standards (non-health based standards). These releases were identified because

exceedence of secondary standards may reduce the useability and, therefore, the value of the

groundwater. Iron, chloride, sulfate and manganese were among the most frequently detected

constituents exceeding secondary standards.

In reviewing air deposition of toxic constituents to great waters, the Agency found a

number of TC constituents, as well as some other chemicals identified in the study. However, it

was not possible to assess the importance of waste to air deposition of toxics to the great waters.

State-Only Hazardous Waste Regulations

Some states have adopted hazardous waste identification rules that are broader or

more stringent than federal RCRA Subtitle C regulations. These expansions reflect state

judgements about gaps in the federal program. Data on hazardous waste regulations from

eight states, California, Michigan, New Hampshire, Oregon, Rhode Island, Texas, Washington,

and New Jersey were considered. Several states regulate additional constituents beyond the TC

list ( 25 for California, 9 for Michigan, and 1 for Washington). California also applies a more

aggressive leaching test, the waste extraction test (WET) to wastes. California also has a test for

combinations of hazardous constituents, in which a combined concentration of the listed

constituents cannot exceed 0.001 percent as a total in the waste. Four states also apply acute

toxicity values (LD50 or LC50) for human or ecological toxicity to the whole waste.

NEXT STEPS

The potential gaps and areas of health and environmental concern identified here will

require further, more detailed examination before regulatory action can be undertaken. For

example, the study highlights risks to ecological receptors and possible inhalation risks to

humans as potential gaps, as well as further evaluation of the adequacy of the TCLP. These

topics were found to be potential gaps in more than one area of the study and will likely be

specific areas of further investigation.

Following release of this report, the Agency will engage in a variety of outreach

activities in identifying appropriate next steps. While the Agency considers this a final report,

comments from interested members of the public are solicited and will be used to help identify

and structure follow-on activities. As noted above, revisions to the characteristics program will

likely, in the long run, involve both regulatory and de-regulatory activities.
Page 1-1

Agreement for Hazardous Waste Characteristics Scoping Study

The Administrator shall perform a study of potential gaps in the coverage of the existing hazardous

waste characteristics. The purpose of the study is to investigate if there are gaps in coverage, and the nature

and extent of the gaps identified. The potential gaps in coverage to be addressed in the study [shall]

incorporate both waste management practices and possible impacts to human health and the environment. With

respect to waste management practices, the study shall, at a minimum, address releases from non-hazardous

waste surface impoundments; waste piles; land treatment units; landfills; and various forms of use

constituting disposal such as road application, dust suppression or use in a product applied to the land. Human

health and environmental impacts to be addressed by the study shall include, but not be limited to: (a) impacts

via non-groundwater exposure pathways, both direct and indirect, to human and ecological receptors; (b)

impacts via the groundwater pathway to ecological receptors; (c) the potential for formation of non-aqueous

phase liquids in groundwater; and (d) impacts via the groundwater pathway to human receptors caused by releases

of toxic constituents not included in the current toxicity characteristic, such as EPA-classified carcinogens,

priority pollutants identified in the Clean Water Act, and solvents used for purposes other than degreasing. 

The Administrator shall complete the study by November 15, 1996, and shall provide the plaintiff with two

copies of the study immediately upon completion.

Environmental Defense Fund, Inc. v. Browner, Civ. No. 89-0598, order granting stipulated motion of EDF and EPA

for amendment of consent decree. May 17, 1996, pp. 18-19.

CHAPTER 1. INTRODUCTION

The U.S. Environmental Protection Agency (EPA), Office of Solid Waste has investigated potential gaps in

the current hazardous waste characteristics promulgated under the federal Resource Conservation and Recovery Act

(RCRA). This report, the Hazardous Waste Characteristics Scoping Study, presents the findings of that

investigation. Chapter 1 presents background information on the Scoping Study as follows:

Section 1.1 describes the purpose and scope of the Scoping Study;

Section 1.2 discusses relevant aspects of the RCRA hazardous waste and non-hazardous

waste programs;

Section 1.3 summarizes the methodology used to prepare the Scoping Study; and

Section 1.4 outlines the remaining chapters and appendices of the Study.

1.1 Purpose and Requirements of the Hazardous Waste Characteristics Scoping Study

As stipulated under an amended consent decree with the Environmental Defense Fund (EDF) (presented in the

text box below), the Agency has investigated potential gaps in the coverage of the existing RCRA hazardous waste

characteristics. The purpose of this Study is to identify potential gaps in coverage and to investigate the nature

and extent of such gaps. Based on the results of the Study, EPA will seek input from interested parties and

determine the appropriate course of action to further address any significant potential gaps identified in the

Study.

1.2 Regulatory Background
 45 Federal Register 33084, May 19, 1980. 1

 58 Federal Register 46049, August 31, 1993. 2

 55 Federal Register 26987, June 29, 1990. 3

 58 Federal Register 46049, August 31, 1993. 4

Page 1-2

This report focuses on wastes that are not currently regulated as hazardous (by virtue of being listed or

exhibiting a characteristic). Industrial wastes are classified either as "hazardous waste" and managed under

Subtitle C of the Resource Conservation and Recovery Act (RCRA) or as "non-hazardous waste" and managed under

Subtitle D of RCRA, primarily under state programs. In the context of this report, the term "non-hazardous

industrial waste" broadly refers to waste that is neither municipal solid waste, special waste, nor considered a

hazardous waste under Subtitle C of RCRA. A brief description of the Agency's hazardous and non-hazardous waste

classification systems is provided below.

Subtitle C of RCRA, as amended, establishes a federal program for the comprehensive regulation of

hazardous waste. Section 1004(7) of RCRA defines hazardous waste as

"a solid waste, or a combination of solid wastes, which because of its quantity, concentration,

or physical, chemical, or infectious characteristics may: (a) cause, or significantly

contribute to an increase in mortality or an increase in serious irreversible, or incapacitating

reversible, illness; or (b) pose a substantial present or potential hazard to human health or the

environment when improperly treated, stored, transported, disposed of, or otherwise managed."

Under RCRA Section 3001, EPA is charged with defining which solid wastes are hazardous by identifying the

characteristics of hazardous waste and listing particular hazardous wastes.

Current hazardous waste characteristics are ignitability, corrosivity, reactivity, and toxicity. The

Agency's definitions of ignitability and reactivity have not changed materially since their adoption in 1980.1

The Agency's definition for corrosivity was last revised in 1993. The Agency's current definition of toxicity was 2

promulgated in 1990, replacing the Extraction Procedure (EP) leach test with the Toxicity Characteristic Leaching 3

Procedure (TCLP) and adding 25 organic chemicals to the list of toxic constituents of concern and establishing

their regulatory levels. The Agency's definition of toxicity was last revised in 1993; however, this revision did 4

not alter the framework for defining this characteristic.

A solid waste is classified as listed hazardous waste if it is named on one of the following four lists

developed by EPA:

Nonspecific source or F wastes (40 CFR 261.31). These are generic wastes, commonly

produced by manufacturing and industrial processes. Examples include spent halogenated

solvents used in degreasing and wastewater treatment sludge from electroplating

processes as well as dioxin wastes, most of which are "acutely hazardous" wastes due to

the danger they present to human health or the environment.

Specific source or K wastes (40 CFR 261.32). This list consists of wastes from

specifically identified industries such as wood preserving, petroleum refining, and
Page 1-3

organic chemical manufacturing. These wastes typically include sludges, still bottoms,

wastewaters, spent catalysts, and residues.

Discarded commercial chemical products or P and U wastes (40 CFR 261.33(e) and (f)). The

third and fourth lists consist of specific commercial chemical products and

manufacturing chemical intermediates. They include chemicals such as chloroform and

creosote, acids such as sulfuric acid and hydrochloric acid, and pesticides such as DDT

and kepone.

Disposal of non-hazardous solid waste is regulated under Subtitle D of RCRA. Subtitle D wastes include

municipal solid waste, special waste, and industrial waste.

Municipal solid waste includes household and commercial solid waste. Household waste is

defined as any solid waste (including garbage, trash, and sanitary waste in septic

tanks) derived from households (including single and multiple residences, hotels and

motels, bunkhouses, ranger stations, crew quarters, campgrounds, picnic grounds, and

day-use recreation areas) (40 CFR 258.2). Commercial waste refers to all types of solid

waste generated by stores, offices, restaurants, warehouses, and other nonmanufacturing activities, excluding residential and industrial wastes (40 CFR 258.2).

Special waste, as used in this document, refers to oil and gas exploration and

production waste, fossil fuel combustion wastes, cement kiln dust, and solid waste from

the extraction, beneficiation, and processing of ores and minerals (40 CFR 261.4).

Non-hazardous industrial waste refers to solid waste generated by manufacturing or

industrial processes that is not a hazardous waste regulated under Subtitle C of RCRA or

a special waste (40 CFR 258.2).

Under Subtitle D, the management of non-hazardous industrial waste in land-based units must comply with

40 CFR Part 257, which establishes minimum federal standards for the management and siting of land-based units. 

Individual states are responsible for implementing 40 CFR Part 257 under their own authority. They have adopted

statutory and regulatory frameworks for management of non-hazardous industrial wastes. These requirements vary

widely from one state to another in terms of their design and operating requirements, monitoring requirements, and

other management requirements such as recordkeeping, closure, post-closure care, and financial responsibility. 

Even within a given state, the non-hazardous industrial waste requirements may vary from facility to facility

depending on the characteristics of the wastes managed and the environmental setting of the waste management unit. 

The Agency is currently developing "voluntary guidelines" for non-hazardous industrial waste management to better

ensure that this waste is managed in a manner that is protective of human health and the environment.

1.3 Approach for Studying Potential Gaps in the Hazardous Waste Characteristics

As shown in Exhibit 1-1, the general approach EPA used to perform the Scoping Study has nine steps. Each

of these steps is discussed below.

Step 1: Characterize Releases from Non-Hazardous Industrial Waste Management

The Agency conducted detailed investigations to identify specific instances of environmental

contamination resulting from the management of non-hazardous industrial wastes. These case studies provide realworld information on releases of these wastes into the environment, the chemicals released and their

concentrations, and the waste management practices and industries involved. The preliminary findings of such
Page 1-4

research were presented in a draft report entitled "Hazardous Waste Characteristics Scoping Study: Environmental

Release Descriptions" (September 24, 1996). EPA held a public meeting on October 10, 1996 to explain and obtain

comments on the draft report. EPA has considered and, where appropriate, incorporated these comments in preparing

this Scoping Study. Chapter 2 summarizes these investigations and Appendix A presents the individual

environmental release descriptions.

Step 2: Categorize Risks Associated with Non-Hazardous Industrial Waste Management

This step identifies categories of risks to human health and the environment that may result from nonhazardous industrial waste management. The underlying premise of this step is that a gap in the hazardous waste

characteristics is any significant risk to human health or the environment associated with non-hazardous

industrial waste management that could be, but is not, addressed by the current characteristics. Thus, this

assessment deals with both:

Hazards that the current hazardous waste characteristics were intended to address,

namely physical hazards such as fire and explosion and toxic groundwater contamination

near waste management facilities; and

Hazards that the characteristics were not intended to address, such as non-groundwater

pathway exposures to toxins, damages to ecological receptors, and natural resource

damages.

EPA identified risks by types of receptors, types of toxic effects and physical hazards, exposure

pathways, and time and spatial scales, as described in Section 3.1. The search for potential risks used broad

definitions of risk and adverse effects and addressed all aspects of non-hazardous industrial waste management,

without any prejudgment as to the likelihood that a risk was significant, whether it could be best addressed by the

characteristics, or whether it was already addressed by other regulations. The results of this risk

classification step were used in identifying and evaluating potential gaps, as described below.

Step 3: Review the Existing Characteristics

The identification of potential gaps continues with a review of the existing definitions of the

characteristics. This step is next for two reasons. First, limitations in the characteristics' effectiveness in

reducing the risks they were intended to address may constitute important potential gaps. When the

characteristics were promulgated, the Agency identified physical hazards and acute toxic hazards during transport

and disposal activities and chronic exposure to groundwater contaminated with waste 
Page 1-5

Insert Exhibit 1-1 Scoping Study Approach
Page 1-6

constituents as being among the most important waste management risks. Reducing these risks remains an important

goal of the characteristics. Second, this analysis lays the groundwork for evaluating other potential gaps.

Step 3 begins by examining the definitions and test methods of the ignitability, corrosivity, and

reactivity (ICR) characteristics, which are essentially unchanged since they were promulgated in 1980. EPA

reviewed the assumptions and approaches used to develop these characteristics and compared the characteristics to

approaches taken to controlling similar hazards under other federal and state regulatory schemes. Step 3 also

examines the definition of the toxicity characteristic (TC), which was designed to protect against human health

risks from exposure to hazardous waste constituents released to groundwater. EPA reviewed new information on the

toxicity, fate, and transport of the TC constituents and improvements in groundwater modeling since the TC was

revised in 1990. The Agency also examined the potential risks from TC constituents through inhalation, surface

water, and indirect pathways and to ecological receptors. Chapter 3 describes these analyses.

Step 4: Identify Gaps Associated with Non-TC Chemicals

Potential gaps in the hazardous characteristics from non-TC chemicals are identified by, first,

identifying two groups of constituents:

"Known" non-hazardous industrial waste constituents: constituents "known" to be

present in non-hazardous industrial wastes, based on the data gathered in the

environmental release descriptions in Step 2, EPA's 1987 Telephone Screening Survey of

non-hazardous industrial waste management facilities, EPA effluent guideline

development documents, and recent hazardous waste listing determinations.

"Possible" non-hazardous industrial waste constituents: constituents on various

regulatory or advisory lists, which were screened for their toxicity, fate, and

transport properties and for a proxy of their occurrence in non-hazardous industrial

waste, using available environmental release data from the 1994 Toxics Release

Inventory.

Then, these two lists of constituents are evaluated and compared and chemicals are classified by physical

properties, chemical composition, use, and origin. Finally, potential gaps were identified by applying multiple

hazard-based screening criteria to specific chemicals and chemical classes. Chapter 4 describes these analyses.

Step 5: Identify Potential Gaps Associated with Certain Natural Resource Damages and Large-Scale

Environmental Problems

As discussed above, steps 3 and 4 respectively examine potential gaps inherent in the current hazardous

waste characteristics and associated with adverse human health or localized ecological effects from constituents

not addressed by the toxicity characteristic. Step 5 addresses a third set of risks associated with non-hazardous

industrial waste management: damages to natural resources that may not have direct human health or ecological

effects, and large-scale environmental problems. The specific risks addressed are:

Pollution of groundwater by constituents that diminish the value and usability of the resource

without threatening human health;

Air pollution through odors that harm the quality of life but may not have severe health effects;

and
Page 1-7

Large-scale environmental problems, including air deposition to the Great Waters, damages from

endocrine disruptors and airborne particulates, global climate change, red tides, stratospheric

ozone depletion, tropospheric ozone and photochemical air pollution and water pollution.

Chapter 5 presents these analyses.

Step 6: Review State Expansions of TC and State Listings

Several states have expanded their hazardous waste management programs to regulate as hazardous certain

wastes or waste constituents that are not hazardous under the federal program. Step 6 examines how states have

expanded their toxicity characteristics and have listed as hazardous certain wastes that are not listed under the

federal program. (Step 3 examines how states have regulated additional wastes by expanding their ICR

characteristics.) These expansions beyond the federal hazardous waste identification rules reflect state

judgments about gaps in the federal hazardous waste program and thereby constitute potential gaps that may merit

further investigation. Chapter 6 presents this analysis. (Chapter 7 summarizes the potential gaps identified in

Chapters 3 through 6.)

Step 7: Evaluate the Industries and Waste Management Practices Associated with Potential Gaps

The evaluation of potential gaps asks two basic questions: (1) What do the qualitative and quantitative

indicators of risk show about the potential gaps? and (2) To what extent are the risks associated with the

potential gaps addressed by other regulations? Steps 7, 8, and 9 address these questions. Step 7 addresses

aspects of the first question. Specifically, it assesses the following:

The amount of non-hazardous industrial wastes generated by various industries;

The frequency with which various chemicals were detected or reported in releases from

various industries;

The management methods associated with the major non-hazardous industrial waste

generators; and

The management practices associated with documented environmental releases of nonhazardous industrial wastes.

Because of data limitations, EPA could not evaluate all potential gaps against all of these criteria. Instead,

this step focuses principally on the potential gaps identified in Steps 3 and 4. Chapter 8 presents this analysis.

Step 8: Assess Regulatory Programs' Coverage of Potential Gaps

The second major issue in evaluating potential gaps is the extent to which the risks are controlled by

existing regulatory or other environmental programs. As noted above, risk-related gaps were identified solely in

terms of their relationship to non-hazardous industrial waste management, and not with regard to whether they

might be controlled under regulatory or other programs. Chapter 9 discusses how major federal and state

regulatory programs may address some of the risks represented by the potential gaps. To the extent that they are

already addressed or could be addressed more effectively by programs other than the hazardous waste regulations,

the potential gaps may not merit further attention by the RCRA Subtitle C program.

Step 9: Present Integrated Evaluation of Nature and Extent of Potential Gaps
Page 1-8

In the final step of the methodology, which is presented in Chapter 10, EPA integrates and summarizes all

of the lines of evidence relating to particular potential gaps in the hazardous waste characteristics. The

summary is presented in the form of several tables. This section also reviews the major data gaps and

uncertainties of the analysis.

1.4 Report Outline

This Scoping Study is organized in the same order as the methodology outlined above.

Chapter 2 characterizes releases from non-hazardous industrial waste management;

Chapter 3 categorizes risks associated with potential gaps in the characteristics and

reviews the existing characteristics to identify potential gaps;

Chapter 4 identifies potential gaps associated with non-TC chemicals;

Chapter 5 identifies potential gaps associated with certain natural resource damages and

large-scale environmental problems;

Chapter 6 identifies potential gaps in the characteristics by reviewing how selected states

have expanded the TC and listed wastes that are not listed as hazardous under the

federal program;

Chapter 7 summarizes the potential gaps identified in Chapters 3 through 6;

Chapter 8 evaluates the extent of the risks presented by potential gaps;

Chapter 9 discusses how major federal and state regulatory programs address the risks

represented by the potential gaps; and

Chapter 10 presents an integrated summary evaluation of the nature and extent of potential

gaps and the associated major analytical limitations and describes the framework

that the Agency will apply in developing a plan for addressing potential gaps in

the hazardous waste characteristics identified in this Study.

The Study also includes several appendices. Appendix A describes the individual environmental releases

summarized in Chapter 2. Appendix B discusses several data sources used to identify environmental releases that

were not successful in finding releases meeting EPA's stringent selection criteria. Appendix C provides a

detailed comparison of the ICR characteristics to related approaches under other federal and state programs. 

Finally, a separate background document contains detailed information and analysis that supplements the

screening-level risk analysis presented in Chapter 3 and the identification of "possible" non-hazardous

industrial waste constituents in Chapter 4.
Page 1-9

CHAPTER 1. INTRODUCTION ........................................................ 1-1

1.1 Purpose and Requirements of the Hazardous Waste Characteristics Scoping Study .... 1-1

1.2 Regulatory Background ................................................... 1-2

1.3 Approach for Studying Potential Gaps in the Hazardous Waste Characteristics ....... 1-4

Step 1: Characterize Releases from Non-Hazardous Industrial Waste Management ... 1-4

Step 2: Categorize Risks Associated with Non-Hazardous Industrial Waste Management1-4

Step 3: Review the Existing Characteristics ................................... 1-4

Step 4: Identify Gaps Associated with Non-TC Chemicals ....................... 1-6

Step 5: Identify Potential Gaps Associated with Certain Natural Resource Damages and

Large-Scale Environmental Problems ................................. 1-6

Step 6: Review State Expansions of TC and State Listings ....................... 1-7

Step 7: Evaluate the Industries and Waste Management Practices Associated with

Potential Gaps .................................................... 1-7

Step 8: Assess Regulatory Programs' Coverage of Potential Gaps ................. 1-8

Step 9: Present Integrated Evaluation of Nature and Extent of Potential Gaps ........ 1-8

1.4 Report Outline .......................................................... 1-8
Page 1-10

Exhibit 1-1 Scoping Study Approach .................................................. 1-5
Page 2-1

CHAPTER 2. RELEASES FROM NON-HAZARDOUS

INDUSTRIAL WASTE MANAGEMENT UNITS

This chapter presents the methodology and results of the Agency's efforts to identify contamination

resulting from the management of non-hazardous industrial wastes. The Agency prepared a draft report entitled

"Hazardous Waste Characteristics Scoping Study: Environmental Release Descriptions" which was released for public

comment on September 25, 1996 (see 61 Federal Register 50295). This chapter summarizes the revised report,

incorporating relevant comments on the draft report. 

This chapter is composed of three sections:

Section 2.1 discusses the criteria, information sources, and methodology used to select

releases to include in the report;

Section 2.2 summarizes the release descriptions and presents findings of the study; and

Section 2.3 presents the major limitations of the study.

The environmental release descriptions described in this chapter are presented in Appendix A of this

Scoping Study.

2.1 Methodology

Based on 1985 data, 7.6 billion tons of non-hazardous industrial waste are generated and managed on-site

annually by 17 major industries in the United States. Despite this large volume of non-hazardous industrial

waste, EPA has few data concerning the releases, human health impacts, or environmental damages caused by such

wastes. To identify such releases for purposes of the Scoping Study, the Agency reviewed readily available

information from a wide variety of data sources. The purpose of this review was not to estimate risks posed, but

rather to characterize releases due to non-hazardous industrial waste management practices. This section

discusses the criteria and methodology used to select releases.

2.1.1 Criteria For Selecting Releases

The Agency considered three major factors in judging whether a release is an appropriate case study for

this report. To be included, a release had to meet all three of the criteria described below:

1. Source of Release. The source of contamination had to be a waste management unit that received

only non-hazardous industrial waste. Releases were excluded if:

a. Evidence suggested that the management unit also received municipal solid waste,

special waste, or RCRA hazardous waste. Many facilities manage municipal, hazardous,

and special wastes in the same waste management units as non-hazardous industrial waste. 

Releases from such units were not included in this report.

b. The source of contamination could not be attributable solely to a non-hazardous

industrial waste management unit. Releases were excluded where contamination (1) was

detected at or near the facility, but the source of contamination was unknown; (2) was
 SMCLs are based on aesthetic considerations (e.g., taste and odor) and are not federally enforceable. 1

Page 2-2

not from a waste management unit (e.g., was a product spill); or (3) was from a

combination of non-hazardous industrial waste unit(s) and municipal, special, or

hazardous waste unit(s).

c. The source of contamination was industrial wastewater discharges that are point source

discharges regulated under Section 402 of the Clean Water Act, as amended.

d. The management method employed would be illegal in most states today. (Facilities were

included if management practices would be legal today, even if no longer employed at a

particular facility.)

2. Evidence of Damage. For purposes of the study, "damage" is considered to be a release exceeding

one of the levels described below. All exceedences were examined for purposes of this scoping

study. Exceedences may not actually represent significant risks. To be included in the Study, a

release from a waste management unit must have caused contamination at levels of potential

concern for that contaminated medium. Levels of potential concern used for this criterion were

often based on federal or state drinking water standards for groundwater contamination and

exceedences of background concentrations for soil contamination. Federal drinking water

standards include maximum contaminant levels (MCLs) and secondary maximum contaminant levels

(SMCLs) . State drinking water standards, which are often stricter than the federal standards, 1

also were considered. Releases were not included if contaminant concentrations were above

background concentrations but below levels of potential concern. If at least one contaminant was

detected at concentrations above a federal or state standard, then data were collected and

presented for all contaminants detected at that site.

3. Test of Proof. Documented evidence must prove that a damage or danger from a non-hazardous

industrial waste management unit has occurred. Evidence was accepted if it met one or more of the

following three tests:

a. Scientific investigation. Damages were found to exist as part of the findings of a

scientific study. Such studies include both extensive formal investigations (e.g., in

support of litigation or a state enforcement action) and the results of technical tests

(e.g., monitoring of wells);

b. Administrative ruling. Damages were found to exist through a formal administrative

ruling, such as the conclusions of a site report by a field inspector, or through

existence of an enforcement action that cited specific health or environmental dangers;

and/or

c. Court decision. Damages were found to exist through a ruling of a court of law or

through an out-of-court settlement.

2.1.2 Approach For Identifying Releases
 "Issue Paper: Potential Damage Cases From On-Site Disposal of Non-Hazardous Industrial Waste," August 1995. 2

 "Damage Cases: On-Site Disposal of Non-Hazardous Industrial Waste," September 1995. 3

Page 2-3

Public Involvement

In the limited time available for preparing this

Scoping Study, the Agency implemented a number of

measures to involve the public in this aspect of

the data collection effort. Specifically, the

Agency contacted the States and facilities

identified in the release descriptions to solicit

comments on draft versions of the release

descriptions. Concurrently, the Agency released a

draft version of its "Hazardous Waste

Characteristics Scoping Study: Environmental

Release Description" report to the public for

comment and review on September 25, 1996 (see 61

Federal Register 50295). This report was made

available through the RCRA Information Center and

the internet via EPA's web page. Next, the Agency

conducted a public meeting on October 10, 1996 in

Arlington, Virginia to solicit comments on the

draft report. Finally, the Agency released a draft

version of the individual release descriptions to

the public for comment and review on October 29,

1996 (see 61 Federal Register 55800).

The Agency investigated eight major data

sources to identify potential releases: 

State Industrial D programs;

State Superfund programs;

Federal Superfund program;

Draft EPA report on construction and

demolition waste landfills;

Federal RCRA corrective action

program;

Other federal and state data

sources;

Newspapers; and

Other literature searches.

EPA identified 112 facilities with

environmental releases from 4 of the 8 data sources. 

As a result, this section summarizes the methodologies

used to investigate only the four sources that

resulted in case studies. Detailed descriptions of

the other four methodologies are presented in Appendix

B. Draft release descriptions were sent to facility

owners/managers for data verification before

inclusion in this final report.

2.1.2.1 State Industrial D Programs

As specified under RCRA Subtitle D, states are the primary regulators of non-hazardous solid waste, also

known as Subtitle D waste. EPA's role is largely limited to establishing guidelines for the development and

implementation of state plans, providing technical assistance, and approving plans that comply with these

requirements. States are responsible for developing and implementing their own plans. EPA identified states with

potential case studies, then reviewed the state files for those potential case studies.

The Agency is currently preparing voluntary guidelines on management standards for non-hazardous

industrial wastes. As part of this effort, in 1995, the Agency contacted representatives from every state in the

continental United States and asked them to identify known or potential environmental damages caused by nonhazardous industrial waste management units. The Agency visited and reviewed state files at four of the five 2

states that reported the largest number of potential case studies, California, Texas, North Carolina, New Mexico,

and Wisconsin, and prepared a report summarizing the results of the visits. The Agency did not visit California 3

because, at the time, California was preparing a comprehensive report on its Solid Waste Assessment Test (SWAT)

program, which included detailed information on environmental releases at non-hazardous industrial waste disposal

sites.
 California Code of Regulations, Title 23, Section 13273. 4

Page 2-4

12 States Included in Analysis

California North Carolina

Florida Pennsylvania

Louisiana Tennessee

Michigan Texas

New Mexico Virginia

New York Wisconsin

For the Scoping Study, the Agency chose to

investigate seven additional states based on the reported

numbers of potential case studies for these States. 

Overall, the Agency focused its review of non-hazardous

industrial waste data on 12 of the 16 states that indicated

having at least 10 potential case studies. The Agency

limited its review to these 12 states due to significant

time constraints associated with the Scoping Study.

As the first step in identifying relevant

releases or case studies, the Agency contacted the states

by telephone to discuss the requirements and purpose of the release descriptions. For states that housed their

files regionally, the Agency contacted each regional office with potential case studies. After scheduling

appointments to review the state files, the Agency visited states to review and collect information about the

specific releases of non-hazardous industrial wastes into the environment at concentrations of concern. The

Agency did not visit California. During these trips, the Agency reviewed readily available documentation on each

potential case study and collected documentation for only those releases that appeared to meet all three of the

criteria described in Section 3.1.1. Over 80 percent of the facilities identified as potential case studies were

excluded from further review, primarily because the facilities co-disposed non-hazardous industrial waste with

municipal, hazardous, or special waste, or because the environmental damages discovered at the facility could not

be directly linked to a non-hazardous industrial waste management unit. On an as-needed basis, EPA also made

follow-up contact with state personnel most knowledgeable about particular sites to obtain additional relevant

information.

To ensure that facility-specific information was accurately compiled and presented, the Agency contacted

the states and facilities by telephone to ask them to review the draft release descriptions prepared for this

report. The Agency sent each state and facility their release descriptions, asked for their written comments on

the descriptions, and incorporated relevant comments.

Review of California's Industrial D Data. In 1984, the California State legislature passed a law that

required testing of water and air media at all solid waste disposal sites. The law also required California's 4

State Water Resource Control Board to rank all solid waste disposal sites in groups of 150 each, according to the

threat these facilities or sites may pose to water quality. California's legislation requires site operators to

submit a water quality "solid waste assessment test" (SWAT) report presenting the following information: 

An analysis of the surface and groundwater on, under, and within one mile of the solid

waste disposal site to provide a reliable indication of whether there is any leakage of

hazardous waste constituents; and

A chemical characterization of the soil-pore liquid in those areas that are likely to be

affected if the solid waste disposal site is leaking, as compared to geologically

similar areas near the solid waste disposal site that are known to not have been affected

by leakage or waste discharge.

To expedite the review of California's Industrial D data, the Agency obtained a copy of California's Solid

Waste Assessment Test database. The Agency reviewed the database to identify those facilities believed to manage

only non-hazardous industrial waste and found to have leaked waste constituents outside the limits of the waste
 Environmental Law Institute, "An Analysis of State Superfund Programs: 50-State Study, 1993 Update," prepared for U.S. 5

Environmental Protection Agency's Office of Emergency and Remedial Response, December 1993.

Page 2-5

Industrial D Case Studies Satisfying Criteria for

Inclusion in the Scoping Study

California 29 Florida 6

Wisconsin 20 New York6

Tennessee 9 North Carolina 6

Louisiana 7 Michigan4

New Mexico 7 Virginia 3

Texas 6 Pennsylvania 1

State Superfund Programs

with 1,000 Sites

California New York

Illinois Ohio

Indiana Pennsylvania

Massachusetts Tennessee

Michigan Texas

Missouri Wisconsin

New Jersey

 

 = State had readily available information.

management unit at levels above California or federal regulatory standards. California's waste classification

system was used to identify facilities believed to manage only non-hazardous industrial waste.

The review of Industrial D data from 12 states

identified a total of 104 releases that met the Agency's

selection criteria. Hundreds of potential cases were

reviewed to identify these releases.

2.1.2.2 State Superfund Programs

Abandoned or uncontrolled hazardous substance

sites not addressed by the federal Comprehensive

Environmental Response, Compensation, and Liability Act

(CERCLA) program may be subject to remediation under the

state Superfund programs. EPA believes that some of these

sites may be contaminated with industrial wastes that would not be hazardous under the current RCRA Subtitle C

requirements.

To expedite the process of identifying relevant

sites and to cover the largest possible percentage of state

Superfund sites, the Agency focused on the states with the

largest programs. These states were identified according

to the Environmental Law Institute's 1993 Analysis of

State Superfund Programs. In July 1996, the Agency 5

identified and contacted 13 states listed as having at

least 1,000 state Superfund sites. Personnel from each of

the 13 states were asked whether they produce publicly

available summaries of their state Superfund programs. 

The Agency obtained the most recent annual state Superfund

reports for Missouri, New Jersey, New York, and Texas and

obtained a printout of California's database for review. 

Due to the significant time constraints associated with

its analysis, the Agency did not pursue information from

other states, which lacked detailed, readily available

information on their Superfund program.

Short published site descriptions for nearly 1,000 state Superfund sites from 5 states, California,

Missouri, New Jersey, New York, and Texas, were reviewed to identify potential case studies that meet the Agency's

selection criteria. A total of 60 sites were identified as potential case studies. The Agency contacted the five

states by telephone to discuss the availability of existing information on those 60 sites. Two states (New York

and Texas) indicated that they had additional information readily available for review. The Agency visited these

states' Superfund offices to review and the additional information. The Agency identified one case study from New

York as meeting all of the selection criteria.

2.1.2.3 Federal Superfund Program
 Conditionally exempt small quantity generators (CESQGs) are defined as generators of less than 100 kilograms per month of

6

hazardous waste. See 40 CFR 261.5.

Page 2-6

The Agency investigated several CERCLA data sources to identify releases relevant to the Scoping Study. 

The vast majority of the CERCLA sites were not expected to meet the Agency's selection criteria for two reasons. 

First, the majority of the sites are contaminated with RCRA hazardous wastes or with releases or spills from

products. These sites will not meet the Agency's selection criteria for source of release. Second, most of the

CERCLA sites contaminated with non-hazardous industrial wastes are also expected to be contaminated with

hazardous wastes. Therefore, it is unlikely that a non-hazardous industrial waste management unit will be

identified as the source of the release at a CERCLA site.

Due in part to the large number (over 1,300) of CERCLA National Priority List (NPL) sites and the

relatively small number of sites likely to meet the Agency's three release selection criteria, the Agency

attempted to identify potential case study sites through telephone discussions with Regional EPA Superfund

personnel and Regional members of the National Association of Remedial Project Managers and the National On-Scene

Coordinator Association. Although the Regional Contacts agreed that the Agency should be able to identify at

least a few case studies from the CERCLA program, they often were unable to identify specific sites. EPA Superfund

staff in Region 4, however, identified two sites apparently meeting the Agency's selection criteria. The Agency

visited Region 4's Superfund office and reviewed and copied the relevant files for these two sites. One of the two

sites met the Agency's selection criteria.

The following federal Superfund data sources were also reviewed; however no releases meeting the Agency's

selection criteria were identified:

Record of Decision (ROD) database;

CERCLA Natural Resource Damage Claims;

CERCLA Characterization Database; and

Exposure assessments performed by the Agency for Toxic Substances and Disease Registry

(ATSDR).

2.1.2.4 Construction and Demolition (C&D) Landfill Report

On May 18, 1995, EPA's Office of Solid Waste published a draft report entitled Damage Cases: Construction

and Demolition Waste Landfills. The report, prepared in support of EPA's rulemaking (60 Federal Register 30963,

June 12, 1995) on conditionally exempt small quantity generators (CESQG), presents information on environmental 6

releases from construction and demolition (C&D) waste landfills, which receive materials generated from the

construction or destruction of structures such as buildings, roads, and bridges. One purpose of the report was to

determine whether the disposal of C&D waste in landfills has threatened or damaged human health or the

environment.

The May 1995 report used three criteria to select potential C&D waste landfill damage cases.

The landfill received predominantly C&D waste, with or without CESQG waste mixed in. 

C&D landfills known to have received significant quantities of municipal, industrial,

or hazardous wastes were excluded.

The use of the site as a C&D landfill had to be the only potential source of the observed

contamination. Sites located near other potential sources of the contamination such as

underground storage tanks were excluded.
Page 2-7

There was documented evidence of groundwater contamination, surface water

contamination, or ecological damage at the site. "Contamination" was defined as an

increase in chemical constituent concentrations above background or an exceedence of an

applicable regulatory standard or criterion attributable to releases from the site.

In preparing the May 1995 report, the Agency searched for C&D landfills meeting these criteria using four

information sources: existing studies of C&D landfills, materials available through the federal Superfund

program, representatives of EPA Regions, and representatives of state and county environmental agencies.

The Agency identified 11 environmental releases in the May 1995 report. Although one of the Agency's

criteria, as listed above, was to eliminate C&D landfills that received significant quantities of municipal or

hazardous wastes, 5 of the 11 landfills received municipal, special, or hazardous wastes. Therefore, for purposes

of this report, the Agency eliminated these five C&D landfill cases. Eliminating the landfills that managed even

small quantities of municipal, special, or hazardous waste, ensures that the reported damages were caused by the

non-hazardous industrial wastes, thereby meeting the Agency's selection criteria for the source of the release.

2.1.3 Release Profile Preparation

The release profiles presented in Appendix A to the Scoping Study were prepared using a standard format. 

This format is discussed below. Because the release profiles were prepared under significant time constraints

using readily available data, detailed descriptions of the facility, wastes, and waste management practices could

not be developed. The data often provided only a brief description of the facility and focused primarily on the

results of the environmental sampling conducted at the facility.

"Facility Overview" discusses the facility's operations, how long the facility was or has been in

operation, the location of the facility, surrounding land uses, the geologic and hydrogeologic conditions at the

facility, and other environmental characteristics, provided this information was available.

"Media Affected" identifies whether the damages are associated with groundwater, surface water, soil,

and/or ecological receptors.

"Wastes and Waste Management Practices" discusses the type(s) of wastes generated at the facility and the

practices employed to manage the wastes including descriptions of the individual waste management units and

groundwater monitoring practices, provided this information was available.

"Extent of Contamination" discusses the groundwater contamination, surface water contamination, and/or

soil contamination at the site. Constituents detected in groundwater or surface water above background levels are

identified and compared to applicable state and federal standards. The maximum detected concentration for all

tested constituents are given. In reporting exceedences of state or federal standards, EPA attempted to exclude

constituents whose upgradient or background concentrations were as high as those in downgradient wells.

"Corrective Actions/Regulatory Actions" discusses any corrective or regulatory actions that have been

recommended, planned, or taken at the site.

"Source" simply identifies the information source(s) used to prepare the release profiles. The main

source of information was the facility-specific files located in state offices.
Page 2-8

2.2 Results

This section discusses the findings of the review of release data. It begins by summarizing the 112

documented release descriptions using the following five categories:

Number of cases by state;

Number of cases by industry;

Number of cases by type of waste management method;

Type of media affected; and

Type and level of contaminants.

Later chapters of this report also present these and additional release description data.

2.2.1 Number of Cases By State

The 112 releases described in this chapter were found in 12 states. Because this report is a Scoping

Study, these case studies were not intended to be geographically or statistically representative of the number of

known or potential releases of non-hazardous industrial wastes identified by the Agency. Although these case

studies are not statistically or geographically representative, they do illustrate the type of releases that have

occurred from non-hazardous industrial waste management units in various parts of the country, as shown in Exhibit

2-1. The case studies were selected based on the availability of data. Due to the limited time available to

collect data, the Agency largely focused its efforts on the states with the most available data on releases from

non-hazardous industrial waste management units. This process identified releases in most areas of the nation,

except the northwest, northern mountain states, and midwest. The states in these regions either were unable to

identify any or identified few potential case studies in the Agency's 1995 efforts to estimate the number of

potential releases from non-hazardous industrial waste management units by state.
Page 2-9

Exhibit 2-1

Number of Release Descriptions By State

The available data on facilities that manage non-hazardous industrial waste indicate that the states

addressed in this report manage some of the largest volumes of non-hazardous industrial waste. Also, seven of the

12 states represented in this report are among the 10 states with the largest number of on-site non-hazardous

industrial waste management units in 1985. Exhibit 2-2 identifies the number

Exhibit 2-2

Number of Management Units & Volume of Waste Managed On-Site, by State (1985)

Rank by Number of 1985 Volume Waste

Number of Management Units in Managed Number of Release

Units State 1985 (Million tons/yr.) Descriptions a a

1 California 2,150 570 29

2 Texas 1,900 590 6

3 Wisconsin 1,720 60 22

4 Pennsylvania 1,475 940 1

5 Georgia 1,080 220 None

6 Illinois 1,005 265 None

7 Ohio 960 155 None

8 Vermont 940 5 None

9 Louisiana 890 170 7

10 North Carolina 855 240 6
Exhibit 2-2 (continued)

Number of Management Units & Volume of Waste Managed On-Site, by State (1985)

Rank by Number of 1985 Volume Waste

Number of Management Units in Managed Number of Release

Units State 1985 (Million tons/yr.) Descriptions a a

Page 2-10

12 Virginia 800 150 6

13 Michigan 785 210 4

14 New York 740 30 8

15 Florida 740 310 7

21 Tennessee 510 245 9

41 New Mexico 140 10 7

Source: "Telephone Screening Survey," U.S. Environmental Protection Agency, 1987. a

of on-site management units and the volume of waste managed on-site in states. (See Chapter 8 for further

discussion of waste generation by industry.)

2.2.2 Number of Cases By Industry

The releases documented in this report were from facilities in 15 2-digit Standard Industry

Classification (SIC) codes. (Industry data are presented at the two-digit level because more specific

classification were not readily available for many facilities.) Over 31 percent of the cases involve Electric,

Gas, and Sanitary Services facilities (SIC 49). All of these facilities are in the refuse system sector (SIC

4953). The top four SIC codes are SIC 49: Electric, Gas, and Sanitary Services, SIC 26: Paper & Allied Products,

SIC 28: Chemical & Allied Products, and SIC 20: Food & Kindred Products. These four industry groups represent

nearly 75 percent of the releases studied or evaluated in this report. Exhibit 2-3 identifies the number of cases

by industry.

Exhibit 2-3

Number of Case Studies by Industry (SIC)

Electric, Gas, & Sanitary Services (49) 35 (31%)

Paper & Allied Products (26) 27 (24%)

Chemical & Allied Products (28) 11 (10%)

Food & Kindred Products (20) 10 (9%)

Primary Metal Industries (33) 6 (5%)

Nonmetallic Minerals, Except Fuels (14) 4 (4%)

Petroleum & Coal Products (29) 4 (4%)

Fabricated Metal Products (34) 3 (3%)

Transportation Equipment (37) 3 (3%)
Exhibit 2-3 (continued)

Number of Case Studies by Industry (SIC)

 U.S. Environmental Protection Agency, Office of Solid Waste, "Non-Hazardous Waste Management: Priority Industries," draft,

7

July 1993.

 U.S. Environmental Protection Agency, Office of Solid Waste, "State Requirements for Non-Hazardous Industrial Waste Management

8

Facilities, September 1995.

Page 2-11

Agricultural Production - Livestock (02) 2 (2%)

Electronic & Other Electric Equipment (36) 2 (2%)

Stone, Clay, & Glass Products (32) 2 (2%)

Apparel & Other Textile Products (23) 1 (1%)

Instruments & Related Products (38) 1 (1%)

Industrial Machinery & Equipment (35) 1 (1%)

These findings are generally consistent with the Agency's previous finding that four industries, Paper and Allied

Products (SIC 26), Chemicals and Allied Products (SIC 28), Petroleum Refining & Related Industries (SIC 29), and

Primary Metal Industries (SIC 33), generated more than 68 percent of the 7.6 billion tons of Industrial D waste

managed on-site in 1985. Although these case studies were identified based on available data and other selection 7

criteria, the number of cases identified per industry and the volume of waste generated per industry appear to be

positively correlated. 

2.2.3 Number of Cases By Type of Waste Management Unit

Four major types of land-based treatment and storage units were identified in the case studies: 

landfills, surface impoundments, land application units, and waste piles. Exhibit 2-4 presents the number of case

studies by waste management unit. Several cases studies discuss more than one unit, therefore, the total number of

units is higher than the total number of case studies. Approximately 93 percent of the case studies involved

landfills and/or surface impoundments. This finding may partly reflect the greater regulatory attention these

units receive from the states, rather than necessarily imply that these units have more frequent releases than

other types of waste management units. Over 90 percent of the landfills and 80 percent of the surface impoundments

included in the case studies are unlined and over 70 percent of the units are no longer being used to manage nonhazardous industrial wastes.

All 50 states have developed regulations for surface impoundments. Approximately 90, 46, and 18 percent

of the states have developed regulations specifically for landfills, land application units, and waste piles,

respectively. The large number of surface impoundments identified in this report is consistent with a finding of 8

EPA's 1987 Telephone Screening Survey that slightly more than half of the facilities that generate and manage onsite non-hazardous industrial waste managed their wastes in
 "State Regulation of Waste Piles, EI Digest Industrial and Hazardous Waste Management," April 1996, pages 16 to 21. 9

 "Nonhazardous Industrial Surface Impoundments: State Regulations and the Environmental Marketplace," Environmental 10

Information, Ltd., 1996, pages 3 to 7.

 "State Requirements for Nonhazardous Waste Land Application Units, EI Digest Industrial and Hazardous Waste Management," May

11

1996.

Page 2-12

Exhibit 2-4

Number of Case Studies By Waste Management Unit

Landfill 73

Surface Impoundment 31

Land Application Unit 12

Waste Pile 4

on-site surface impoundments. The 1987 survey also indicated that 35 percent of the facilities managed their

wastes on-site in waste piles, 19 percent in landfills, and 18 percent in land application units.

Many states apply their non-hazardous industrial waste regulations on a site-by-site basis and,

therefore, not all facilities in a state are subject to the same data collection and recordkeeping requirements. 

One recent report indicates that even states with waste pile regulations do not appear to be actively enforcing

control, monitoring, and closure requirements, which may partly explain the small number of release descriptions

for waste piles.9

The large number of landfills and surface impoundments in the release descriptions appears consistent

with the type of management units used by the primary industries included in this report. Reportedly, the food

processing industry has the largest number of non-hazardous industrial waste surface impoundments and land

application units. Other major industries identified in this report with a large number of surface impoundments 10,11

and landfills include the paper, electric power, chemical, mining, and metal finishing industries.

2.2.4 Type of Media Affected

Nearly 98 percent of the case studies involved groundwater contamination. Approximately 31 percent of

the case studies involved contamination of surface water or soil. No case studies had documented damages from

releases to the air and nearly 30 percent of the case studies affected multiple media.

The predominance of groundwater contamination is consistent with the use of groundwater monitoring as the

most common method of detecting releases from waste management units. Surface water is not as routinely monitored

as groundwater. Surface water sampling is seldom conducted at a facility until a release is identified. Soil

sampling is conducted much less frequently than groundwater monitoring, and like surface water sampling, is seldom

conducted until a release has been identified. Few states regulate air emissions from non-hazardous industrial

waste management units. Thus, it is not surprising that no cases of damage from releases to the air were documented

in the case studies collected for this report.
Page 2-13

2.2.5 Types of Contaminants Released

The number of and types of contaminants routinely analyzed for in groundwater and other types of samples

varies among states and facilities. Although most facilities included in the case studies were monitored for a

wide range of constituents, the 20 constituents most commonly detected to exceed regulatory levels were

inorganics. Approximately 50 constituents were detected three or more times, and 70 constituents were detected

fewer than three times. Exhibit 2-5 identifies all of the TC constituents that were detected in the case studies,

Exhibit 2-6 presents all of the constituents with SMCLs that were identified in the case studies, and Exhibit 2-7

identifies the other constituents that were detected in at least three case studies. The exhibits also identify

the number of cases where each constituent was detected, the number of times the constituent was detected above at

least one regulatory level, the regulatory levels, the average maximum and the highest maximum detected

concentration identified in the case studies, and the range of the ratio of the highest detected constituent

concentrations to regulatory standards. Note, only constituents with regulatory standards are included in

Exhibits 2-5, 2-6, and 2-7.

Many inorganic constituents were elevated in groundwater monitoring wells. Constituents that exceeded

state groundwater protection standards or federal drinking water standards most frequently were:

Iron (49 detections) Cadmium (17 detections) 

Chloride (32 detections) Benzene (16 detections)

Manganese (34 detections) Arsenic (15 detections)

Sulfate (29 detections) Zinc (13 detections)

Lead (22 detections) Aluminum (12 detections)

Chromium (21 detections) Nitrate (12 detections)

Six of the constituents identified above (iron, chloride, manganese, sulfate, zinc, and aluminum) have drinking

water standards that are based only on SMCLs.

A total of 25 TC constituents have been detected in the release descriptions. Exhibit 2-5 identifies 20 of

the 25 TC constituents detected. Five TC constituents (2,4,6-trichlorophenol, 2,4-dinitrotoluene, o-cresol, pcresol, and methyl ethyl ketone) were not included in Exhibit 2-5 because there were no federal or state standards

established for them. All but 2 of the 20 TC constituents identified in Exhibit 2-5 (carbon tetrachloride, 1,4-

dichlorobenzene) were detected above a federal or state standard. The majority (85 percent) of the TC

constituents detected above a federal or state standard exceeded the standards by at least 1 time, 60 percent

exceeded by 10 times, 50 percent exceeded by 100 times, 20 percent exceeded by 1,000 times, 10 percent exceeded by

10,000 times, and none exceeded by at least 100,000 times. The average maximum detected concentrations for five of

the TC constituents (arsenic, benzene, selenium, vinyl chloride, and lindane) exceeded the TC
Page 2-14

Exhibit 2-5

TC Contaminants Detected in Case Studies

Constituent (mg/l) Constituents Standards (mg/l) (mg/l) (mg/l) Standards

TC Level With Detected Federal/ State Concentration Federal/State

Case Studies Concentrations Above Detected Concentration to

Case Studies with Ratio of Highest

Detected Range of Average Maximum Highest Maximum Detected

Federal/State Detected

Standards Concentration

Lead 5 37 22 0.0015 - 0.05 1.3 28 560 - 18,667

Chromium 5 36 21 0.01 - 0.1 2.3 58 580 - 5,800

Arsenic 5 29 15 0.005 - 0.05 28.4 595 11,900 - 119,000

Cadmium 1 28 17 0.0004 - 0.005 0.2 3 600 - 7,500

Barium 100 28 11 0.2 - 2 31.1 630 315 - 3,150

Benzene 0.5 23 16 0.0005 - 0.001 1.4 15 15,000 - 30,000

Mercury 0.2 19 6 0.0002 - 0.002 0.002 0.007 3.5 - 35

Selenium 1 18 6 0.01 - 0.05 2.2 27 540 - 2,700

Trichloroethylene 0.5 15 7 0.0005 - 0.005 0.03 0.14 28 - 280

Vinyl chloride 0.2 13 6 0.0002 - 0.002 2.9 8.6 4,300 - 43,000

Silver 5 12 3 0.01 - 0.1 0.006 0.01 0.1 - 1

Chlorobenzene 100 9 2 0.05 0.025 0.05 1

Chloroform 6 8 2 0.0006 - 0.08 0.11 0.4 105 - 667

Tetrachloroethylene 0.7 7 3 0.005 0.0085 0.026 5

1,4-Dichlorobenzene 7.5 5 0 0.015 - 0.075 0.017 0.035 0.5 - 2.3

Carbon tetrachloride 0.5 4 0 0.005 0.0017 0.004 0.8

Pentachlorophenol 100 2 2 0.001 0.036 0.063 63

Lindane 0.4 2 2 0.0002 0.66 1.2 6,000

1,2-Dichloroethane 0.5 2 2 0.005 0.016 0.02 4

Heptachlor 0.008 1 1 0.0004 0.002 0.002 5
Page 2-15

Exhibit 2-6

Contaminants with SMCLs Detected in Case Studies

Constituent/ Property Constituents Standards Standards (mg/l) (mg/l) (mg/l) Standards

Case Studies With Concentrations Above Range of Concentration to

Detected Federal/State Federal/State Federal/State

Case Studies with Ratio of the Highest

Detected Average Maximum Highest Maximum Detected

Detected Detected

Concentration Concentration

pH 66 24 6.5 - 8.5 5.4 12.4 1.5 - 1.9

(unitless) (unitless) (unitless)

Iron 54 49 0.15 - 0.3 244 4,400 14,667 - 29,333

Chloride 52 32 125 - 250 1,825 37,200 149 - 297

Sulfate 50 29 125 - 500 2,273 26,000 52 - 208

Total dissolved 48 30 500 - 1,000 7,033 98,164 98 - 196

solids

Manganese 39 34 0.0025 - 0.3 10 97 323 - 3,880

Zinc 33 13 0.05 - 5 20 262 52 - 5,240

Copper 17 2 0.13 - 1.3 0.15 0.9 0.7 - 7

Aluminum 12 12 0.05 - 0.2 235 1,933 9,665 - 38,660

Fluorides 12 4 0.44 - 4 12 98 25 - 223
Page 2-16

Exhibit 2-7

Other Contaminants Detected in At Least Three Case Studies

Constituent Constituents Standards Standards (mg/l) (mg/l) (mg/l) Standards

Case Studies With Concentrations Above Range of Concentration to

Detected Federal/State Federal/State Federal/State

Case Studies with Ratio of the Highest

Detected Average Maximum Highest Maximum Detected

Detected Detected

Concentration Concentration

Sodium 40 8 20 -160 1,292 15,600 98 - 780

Nitrate 33 12 2 - 10 46 560 56 - 280

Magnesium 32 3 35 - 420 140 1,495 4 - 43

Toluene 20 7 0.07 - 1 0.62 6.7 7 - 96

Phenol 18 10 0.001 - 1.2 6.3 60 50 - 60,000

Ammonia 16 2 2 55.3 410 205

Nickel 14 4 0.08 - 0.1 0.1 0.5 5 - 6.3

Nitrite 11 9 1 18.9 64 64

Xylenes 10 1 0.124 - 10 2 4.8 0.5 - 39

1,1-Dichloroethane 10 0 0.7 0.18 1 1

Acetone 9 1 0.7 1.4 10.6 15

Nitrogen 8 0 2 - 10 8.1 57.6 6 - 29

Dichloromethane 7 4 0.005 - 0.015 0.6 4 267 - 800

Ethylbenzene 7 3 0.14 - 0.7 0.3 0.9 1.3 - 6.4

Vanadium 7 0 0.014 0.1 0.4 31

cis-1,2- 7 3 0.07 0.081 0.24 3

Dichloroethylene

Beryllium 7 6 0.004 - 1.1 0.25 1.7 2 - 425

Cyanide 6 2 0.04 - 0.2 0.09 0.4 2 - 10

Boron 6 1 2.9 40.4 82 28

Cobalt 5 0 0.005 0.083 0.16 32

Naphthalene 5 1 0.008 3.3 14.2 1,775

Antimony 5 4 0.006 0.67 3 500

trans-1,2- 4 1 0.01 0.0016 0.052 5

Dichloroethylene

Thallium 4 2 0.002 0.0048 0.01 5
Page 2-17

regulatory levels established for these constituents and the highest maximum detected concentrations for over half of the identified TC constituents exceed TC

regulatory levels.

All SMCLs or similar state standards, except those for foaming agents, color, odor, and corrosivity, were violated by one or more release

descriptions. As shown in Exhibit 2-6, the majority (90 percent) of the SMCL constituents exceeded the standards by at least 1 time, 80 percent exceeded by 10

times, 40 percent exceeded by 100 times, 20 percent exceeded by 1,000 times, 10 percent exceeded by 10,000 times, and none exceeded by at least 100,000 times. 

(Because silver has both a TC level and an SMCL, it is included in Exhibit 2-5 with the other TC constituents.) SMCLs are based on aesthetic considerations

(e.g., taste and odor) and are not federally enforceable. Therefore, exceedences of the SMCLs do not necessarily indicate a potential danger to human health

or the environment. Sixteen of the case studies (14 percent) were identified based only on an exceedence of an SMCL. This type of contamination is discussed

further in Chapter 5.

Exhibit 2-7 identifies 24 other constituents that were detected in the release descriptions. All but four of the constituents in Exhibit 2-7 (1,1-

dichloroethane, nitrogen, vanadium, and cobalt) were detected above a federal or state regulatory level. Half (50 percent) of these other constituents

exceeded one of the standards by at least 10 times, 13 percent exceeded by 100 times, 4 percent exceeded by 1,000 times, and none exceeded by at least 10,000

times.

Constituents managed in landfills were detected in samples nearly three times more frequently than constituents managed in surface impoundments. All

of the constituents presented in Exhibits 2-5, 2-6, and 2-7 are associated with wastes managed in landfills. Approximately 81 percent of the constituents are

associated with both landfills and surface impoundments, 33 percent are associated with landfills, surface impoundments, and land application units, 33

percent are associated with landfills, surface impoundments, and waste piles, and 12 percent are associated with all 4 waste management units. The

constituents that are associated only with landfills are antimony, beryllium, boron, cobalt, cyanides, silver, and thallium. 

Exhibit 2-8 identifies the 10 constituents for each of the 6 industries that were identified most frequently in the case studies. As the exhibit

illustrates, inorganics are the most commonly detected chemicals. The commonly detected constituents are chloride, pH, iron, lead, total dissolved solids,

manganese, sulfate, magnesium, zinc, and arsenic. 

2.3 Major Limitations

The findings presented in this chapter must be interpreted with care for several reasons, including the limited time available to collect data,

potentially unrepresentative data, and the Agency's stringent release selection criteria. Each of these major limitations is discussed in detail below.

Data were collected under significant time constraints. The significant amount of data included in this chapter were collected and analyzed over a

four-month period. During this time the Agency reviewed previously collected data, readily available databases, and reports; identified and contacted

appropriate state and federal personnel; visited state and EPA Regional offices; reviewed facility files; prepared case study summaries; developed a database

to analyze the data; performed QA/QC on the data; sent draft case studies to states and facilities for review; prepared a draft report for public review; and
Page 2-18

incorporated comments into the report, as appropriate. Due to the time constraints of the consent decree, the

Agency had to carefully prioritize its efforts and, in doing so,
Page 2-19

Exhibit 2-8

Most Common Constituents By Industry

Industrial Classification Code Number of Case Studies in Which the

(SIC) Constituent Constituent Was Detected

Refuse Systems (495) pH 19 *

Iron 14 *

Manganese 13 *

Sulfate 13 *

Lead 12

Chloride 11 *

Magnesium 10

Nitrate 10

Total dissolved solids 10 *

Trichloroethylene 10

Paper & Allied Products (26) pH 22 *

Chloride 21 *

Iron 21 *

Sulfate 20 *

Sodium 15

Calcium carbonate 12

Calcium 11

Magnesium 11

Zinc 11

Total dissolved solids 10 *

Chemical & Allied Products (28)Benzene 7

Chromium 7

Iron 7

*

Lead 6

Manganese 6

*

Sulfate 6

*
Exhibit 2-8 (continued)

Most Common Constituents By Industry

Industrial Classification Code Number of Case Studies in Which the

(SIC) Constituent Constituent Was Detected

Page 2-20

Chemical & Allied Products (28)Total dissolved solids 6

(Cont.)

*

Zinc 6

Arsenic 5

Chloride 5

*

Food & Kindred Products (20) Nitrite 6

Nitrate 5

Nitrogen 5

pH 4

*

Total dissolved solids 4

*

Total filterable residue 4

Calcium 3

Chloride 3

*

Magnesium 3

Sodium 3

Non-Metallic Minerals, Except Arsenic 4

Fuels (14)

Iron 4

*

Lead 4

Manganese 4

*

pH 4

*

Cadmium 3

Chloride 3

*

Copper 3

Nickel 3

Potassium 3
Exhibit 2-8 (continued)

Most Common Constituents By Industry

Industrial Classification Code Number of Case Studies in Which the

(SIC) Constituent Constituent Was Detected

Page 2-21

Primary Metal Industries (33) Lead 4

Chromium 3

Aluminum 2

Arsenic 2

Barium 2

Cadmium 2

Chloride 2

*

Mercury 2

Nickel 2

Zinc 2

 Constituents with Secondary Maximum Contaminants. *

may have eliminated or missed a number of potential case studies that could have been included in the report if

additional data were available and/or additional time was spent collecting and reviewing data.

Data may be unrepresentative and/or out-of-date. In this report, the Agency did not attempt to estimate

the proportion of non-hazardous management facilities currently experiencing constituent releases. Due primarily

to the limited time available for data collection and analysis, the Agency relied upon readily available data. The

Agency did not perform any new sampling or collect new data from facilities managing non-hazardous industrial

wastes. Nor did the Agency perform a comprehensive review of previously collected state and federal data for all

non-hazardous industrial waste management facilities. State file reviews were conducted in one to three days per

state and were limited to those states that indicated having files of release incidents that met the Agency's

selection criteria. Although the collection of release descriptions is not statistically representative in any

way, these cases are indicative of the type of releases associated with the management of non-hazardous industrial

waste.

Because only readily available data were analyzed, the data may not reflect current waste generation and

management practices at the particular facility. Environmental contamination resulting from waste disposal

practices may take many years to become evident; some releases described in this report occurred over 20 years ago. 

The documented releases may have resulted from particular waste generation and disposal practices or other

conditions that no longer exist. Specifically, process feedstocks, processing operations, waste characteristics,

and/or waste management practices may have changed. Facilities may no longer manage their wastes in unlined units

or in environmentally sensitive areas. Therefore, releases associated with a waste do not necessarily demonstrate

that current waste management practices or regulations need to change. Conversely, the failure of a site to
Page 2-22

exhibit documented damages at present does not necessarily suggest that waste management has not or will not cause

damage. The Agency, however, believes that information on dangers posed by past waste management practices is

useful in demonstrating the potential for human health or environmental damages.

The extent to which the findings can be used to draw conclusions concerning the relative performance of

waste management practices among states or across industry sectors is also severely limited by variations in

recordkeeping, monitoring, and other state requirements. Recordkeeping and monitoring procedures vary

significantly among the states. Several states have complete and up-to-date central enforcement or monitoring

records on facilities that generate and manage non-hazardous industrial wastes. Where states have such records,

information on releases may be readily available. Thus, states with the most complete and accessible monitoring

information on non-hazardous industrial wastes may appear to have more releases than states with less centralized

information management programs.

Stringent selection criteria. The Agency developed stringent selection criteria to help focus its data

collection efforts and to avoid any misrepresentation of release incidents. By focusing solely on releases

clearly associated with non-hazardous industrial waste management units, the Agency excluded numerous release

incidents caused by accidental releases and spills of products. Although these incidents may have been caused by

hazardous constituents similar to those managed in non-hazardous industrial waste management units, and may pose

similar hazards, the Agency did not analyze these cases, largely because of the inability of RCRA to prevent

product releases. 

The Agency also excluded release incidents that could not be linked to specific facilities. Thus, cases

of groundwater and surface water contamination caused by multiple facilities were excluded because the source of

the releases could not be associated with specific facilities or waste management units.

The Agency also excluded numerous release incidents associated with facilities that manage hazardous,

municipal, or special wastes in addition to non-hazardous industrial waste. Facilities that manage hazardous,

municipal, or special wastes frequently co-dispose of their non-hazardous industrial wastes in the same or

adjacent waste management units. Due to the close proximity of these different units, sampling results generally

cannot identify the specific unit associated with the release. Thus, the Agency excluded cases where nonhazardous industrial waste was managed in the same or adjacent waste management units as hazardous, municipal, or

special wastes, because the source of the release could not clearly be associated with the non-hazardous

industrial waste.
Page 2-23

CHAPTER 2. RELEASES FROM NON-HAZARDOUS INDUSTRIAL WASTE MANAGEMENT UNITS 2-1

2.1 Methodology ..................................................... 2-1

2.1.1 Criteria For Selecting Releases ................................ 2-1

2.1.2 Approach For Identifying Releases ............................. 2-3

2.1.2.1 State Industrial D Programs ............................ 2-3

2.1.2.2 State Superfund Programs ............................. 2-5

2.1.2.3 Federal Superfund Program ............................ 2-6

2.1.2.4 Construction and Demolition (C&D) Landfill Report ....... 2-6

2.1.3 Release Profile Preparation ................................... 2-7

2.2 Results .......................................................... 2-8

2.2.1 Number of Cases By State ................................... 2-8

2.2.2 Number of Cases By Industry ................................ 2-10

2.2.3 Number of Cases By Type of Waste Management Unit ........... 2-11

2.2.4 Type of Media Affected .................................... 2-12

2.2.5 Types of Contaminants Released ............................. 2-13

2.3 Major Limitations ................................................ 2-17
Page 2-24

Exhibit 2-1 Number of Release Descriptions By State ..................................... 2-9

Exhibit 2-2 Number of Management Units & Volume of Waste Managed On-Site, by State (1985) 2-9

Exhibit 2-3 Number of Case Studies by Industry (SIC) ................................... 2-10

Exhibit 2-4 Number of Case Studies By Waste Management Unit .......................... 2-12

Exhibit 2-5 TC Contaminants Detected in Case Studies .................................. 2-14

Exhibit 2-6 Contaminants with SMCLs Detected in Case Studies ........................... 2-15

Exhibit 2-7 Other Contaminants Detected in At Least Three Case Studies .................... 2-16

Exhibit 2-8 Most Common Constituents By Industry ..................................... 2-18
Page 3-1

CHAPTER 3. POTENTIAL GAPS ASSOCIATED WITH

HAZARDOUS WASTE CHARACTERISTICS DEFINITIONS

This chapter examines how well the existing hazardous waste characteristics address the types of risk

they were intended to address, that is, their target risks. It also addresses certain other or non-target risks

that are closely associated with the definitions of the hazardous characteristics. This evaluation of potential

gaps begins by examining the characteristics' definitions and test methods. This approach is used for two

reasons. First, limitations in the characteristics' effectiveness in reducing their target risks may themselves

constitute important potential gaps. When the characteristics were promulgated, the Agency identified physical

hazards and acute toxic hazards during transport and disposal activities, along with chronic exposure to

groundwater contaminated with specific waste constituents, as being among the most important waste management

risks. Reducing these risks remains an important goal of the characteristics. Second, this analysis lays the

groundwork for evaluating other potential gaps. Specifically, risk-based screening methods are used to evaluate

non-target risks from non-ground-water pathways associated with the toxicity characteristic (TC) analytes. The

findings of that analyses are used to identify potential gaps associated with a wider universe of known and

possible non-hazardous industrial waste constituents, as discussed in Chapter 4.

This chapter revisits many of the assumptions and approaches used to develop the existing hazardous waste

characteristics. The ignitability, corrosivity, and reactivity (ICR) characteristics are essentially unchanged

since their initial promulgation in 1980. The TC characteristic was revised in 1990, but has not changed

materially since then. Potential gaps in these characteristics may be identified if the state of knowledge about

risks addressed by the characteristics has improved since the characteristics were promulgated; risks that were

not specifically addressed may now be identified as more important, such as risks from releases to surface water,

inhalation, and indirect pathways and ecological risks. In addition, the tests used to identify wastes with

hazardous characteristics do not reliably identify all of the risks the characteristics were intended to address.

The following sections address these issues. Section 3.1 reviews the statutory and regulatory language

related to the types of risks the hazardous waste characteristics were intended to address and discusses the major

categories of waste management risks addressed and not addressed by the current characteristics. Sections 3.2

through 3.4 discuss potential gaps associated with the ignitability, corrosivity, and reactivity characteristics,

respectively. In addition, a detailed comparison of the ICR characteristics can be found in Appendix C. Section

3.5 discusses the potential gaps associated with the toxicity characteristic, including updated risk information

on the TC analytes. Section 3.6 evaluates the toxicity characteristic leaching procedure (TCLP) as a predictor of

constituent releases and potential risk.

3.1 Types of Risks Addressed by RCRA Hazardous Waste Characteristics

3.1.1 Statutory and Regulatory Framework

The RCRA hazardous waste characteristics are a vital part of the comprehensive program of hazardous waste

management established by Subtitle C of RCRA, as amended. Three provisions of the RCRA statute are particularly

relevant to identifying and expanding the hazardous waste characteristics (and listing hazardous wastes).

First, Section 1004(7) defines hazardous waste as "a solid waste, or combination of

solid wastes, which because of its quantity, concentration, or physical, chemical, or

infectious characteristics may (A) cause, or significantly contribute to an increase in

mortality or an increase in serious irreversible, or incapacitating reversible,

illness; or (B) pose a substantial present or potential hazard to human health or the
 45 Federal Register 33108-33110, May 19, 1980. 1

Page 3-2

environment when improperly treated, stored, transported, or disposed of, or otherwise

managed." This definition indicates the general types of risks that the hazardous waste

management regulations are meant to address.

Second, Section 3001(a) requires EPA to "develop and promulgate criteria for

identifying the characteristics of hazardous waste, and for listing hazardous wastes, .

. . taking into account toxicity, persistence, and degradability in nature, potential

for accumulation in tissue, and other related factors such as flammability,

corrosiveness, and other hazardous characteristics. Such criteria shall be revised

from time to time as may be appropriate."

Third, Section 3001(b) requires EPA to "promulgate regulations identifying the

characteristics of hazardous waste, and listing particular hazardous wastes, . . . 

which shall be based on the criteria promulgated under [Section 3001(a)] and shall be

revised from time to time thereafter as may be appropriate." The Section also requires

EPA to "identify or list those hazardous wastes which shall be subject to the [hazardous

waste regulations] solely because of the presence in such wastes of certain constituents

(such as identified carcinogens, mutagens, or teratogens) at levels in excess of levels

which endanger human health."

In response to the mandate of Section 3001(a), EPA promulgated two sets of criteria for identifying the

characteristics of hazardous waste in 40 CFR 261.10(a). The first set of criteria reflects the statutory

definition of hazardous waste and the types of risks that the characteristics are intended to address:

"(1) The solid waste may

(i) cause, or significantly contribute to, an increase in mortality or an increase in

serious irreversible, or incapacitating reversible, illness; or

(ii) pose a substantial present or potential hazard to human health or the environment

when it is improperly treated, stored, transported, disposed, or otherwise managed."

The second set of criteria considers implementation factors:

"(2) The characteristic can be

(i) measured by an available standardized test method which is reasonably within the

capability of generators of solid waste or private sector laboratories that are

available to serve generators of solid waste; or 

(ii) reasonably detected by generators of solid waste through their knowledge of their

waste."

As stated in the May 19, 1980, final rule, EPA adopted the second set of criteria because the primary

responsibility for determining whether wastes exhibit a characteristic rests with generators, for whom standard

and available testing protocols are essential. This Scoping Study addresses these criteria for the current 1
Page 3-3

characteristics in only a general way. The Agency, however, will carefully consider these factors when deciding

the appropriate course of action for addressing any potential gaps in coverage that are identified in this Study.

The following sections review the nature of the risks to human health and environment potentially posed by

non-hazardous industrial waste management. These risks are associated with physical hazards, acute toxic hazards

to humans, chronic toxic hazards to humans, risk to non-human receptors, and other hazards. In the discussion

below, risks addressed by the hazardous waste characteristics are distinguished from those risks not directly or

adequately addressed. The purpose of this section is to develop a preliminary list of possible gaps in the

characteristics. At this stage, few judgments are made as to the nature and severity of any potential gaps. 

Instead, the remainder of this Report investigates these potential gaps.

3.1.2 Risks Associated with Physical Hazards

Physical hazards include agents that cause direct physical harm such as thermal burns, wounds,

contusions, or eye injuries, in contrast to agents causing harm through chemical burns or toxic effects. These

hazards are controlled primarily through the ignitability, corrosivity, and reactivity (ICR) characteristics. 

EPA patterned these characteristics after similar regulations promulgated by the U.S. Department of

Transportation, the National Fire Protection Association, and other organizations.

The ICR characteristics are intended primarily to protect waste management and transportation workers

against hazards often associated with hazardous materials. These hazards include flammability, explosivity, and

the propensity to react violently with other wastes, corrode containers, and directly injure skin and eyes during

transport or management activities. In addition, these characteristics are intended to prevent the facilitated

release and transport of hazardous waste constituents. For example, the corrosivity test is designed, in part, to

identify wastes that, because of their acidity or basicity, may facilitate the solubilization of metals from

wastes. This solubilization increases the potential impact of metals in groundwater, thereby increasing the

likelihood of risks to human health via contaminated groundwater.

For the purposes of this Scoping Study, the question is: What physical risks may arise from the management

of non-hazardous industrial wastes that are currently not covered by the characteristics? Several potentially

significant physical risks are not effectively addressed by the hazardous characteristics. Some of the potential

gaps arise from specific definitions of the ICR characteristics. These potential gaps, which are discussed in

more detail in Sections 3.2 through 3.4, include:

The lack of coverage of corrosive solids;

The decision not to address liquids with moderate flash points;
 55 Federal Register 11809, March 29, 1990. 2

Page 3-4

Limitations in the test procedures prescribed for reactivity; and

Potential limitations of pH as an adequate indicator of corrosivity.

These issues relate to protecting waste management and transportation workers from physical injuries, except

where explosions or fire might release toxic particulates that could harm nearby residents. Physical hazards to

residents near management facilities are not considered, based on the assumption that the general public has

limited access to non-hazardous industrial waste management facilities.

Other physical concerns relate to facilitated pollutant transport. For example, the corrosivity

characteristic was not intended to address corrosion to liners or any materials other than steel or to prevent

facilitated transport of organic chemicals through solubilization in discarded solvents. EPA considered, and

decided to omit, a “solvent override” provision in the 1990 TC rule that would have classified as hazardous wastes

with more than a specified concentration of hazardous organic solvents. The Agency, however, left open the

possibility that such a provision could be reconsidered if additional data warrant it. A related issue is the 2

potential formation of dense and light non-aqueous phase liquids (DNAPLs and LNAPLs). They are a potential

concern both because they may facilitate pollutant transport and they have the potential for damaging groundwater

resources and generating high remediation costs. Section 4.4 discusses the issue of DNAPL and LNAPL formation.

3.1.3 Acute Toxic Hazards to Humans

The hazardous waste characteristics address some potential health risks from acute exposures to toxic

chemicals. They limit the potential for release of toxic chemicals during transportation, storage, treatment, and

disposal and resulting from fires, explosions, or violent reactions. There are no specific quantitative

benchmarks that define acceptable acute exposure limits, however. The main focus of the ICR characteristics is on

protecting workers, although the general public is implicitly protected under the assumption that protecting onsite workers would protect more distant resident populations as well. Sections 3.2 through 3.4 discuss potential

gaps in the ICR characteristics.

The characteristics were not intended to protect against other acute systemic toxicity hazards. Direct

contact with a waste, in theory, could result in the absorption of an acutely toxic dose of a waste constituent from

a non-corrosive waste. The Agency, however, considered this scenario to be highly improbable for non-hazardous

industrial waste mismanagement. Similarly, acute exposures via contaminated surface or groundwater are possible,

but were considered much less likely to be important than chronic toxicity under most circumstances. Because the

TC focuses on the groundwater pathway, with the attendant long-term transport and dilution of pollutants, EPA

assumed that chronic exposures would be dominant in determining the potential for adverse health effects. Section

3.5.6 discusses the potential for acute adverse effects of exposure to the TC analytes and Section 4.6 addresses

acute risks from non-TC constituents.

3.1.4 Chronic Toxicity Risks to Humans

As noted above, EPA intended the TC to be the major vehicle for controlling chronic health risks, although

the reactivity and corrosivity characteristics also were intended to prevent releases that facilitate exposure to

waste constituents. Although RCRA Section 3001 identifies a range of types of toxic effects of concern (toxicity,

carcinogenicity, mutagenicity, and teratogenicity), the implementation of the TC is limited to 40 chemicals for

which toxicity and groundwater fate and transport data were available when the Agency revised the characteristic

in 1990. In addition, the levels of protectiveness achieved by the TC leachate concentration standards were

determined using fate and transport models and assumptions that were current at the time. To the extent that the
Page 3-5

toxicity data and groundwater fate and transport models have changed or improved in the six years since the TC was

promulgated, its expected level of protectiveness may also have changed. Section 3.5 discusses in detail

potential gaps associated with the level of protectiveness of the TC in light of recent advances in toxicology and

groundwater modeling.

The TC was not intended to address several potentially important risks. These risks have been identified

as significant contributors to risks from some hazardous waste constituents and management technologies, and

might apply to non-hazardous industrial waste management as well. Probably the most important risks potentially

not directly addressed by the TC are associated with exposure pathways other than groundwater. The TC did not

attempt to address these risks because groundwater was thought to be the dominant risk pathway for waste

management. Upon re-examining potential non-hazardous industrial waste management and mismanagement scenarios,

however, EPA recognizes that other pathways also may be important.

One pathway not directly addressed by the TC is the direct inhalation of volatile or particulate-bound

waste constituents to air from waste management units during normal operation or after closure. Such exposures to

on-site workers and off-site receptors through direct inhalation may be significant for some constituents. Other

potentially important pathways include the surface water pathway and “indirect” pathways arising from air

releases (e.g., air deposition to crops), runoff, and the discharge of contaminated groundwater to surface water. 

Also, bioaccumulation of certain contaminants in aquatic and/or terrestrial food chains could result in human

exposures through the consumption of contaminated fish, shellfish, livestock, and game animals. In Section 3.5, a

screening-level risk assessment and other information clarify the significance of these pathways for the TC

analytes. Chapter 4 extends the screening-level analysis to non-TC constituents.

3.1.5 Risks to Non-Human Receptors

Neither the TC nor the ICR characteristics were established specifically to reduce risks to non-human

receptors. Such risk reduction, to the extent that it occurs, is a byproduct of the control of human health risks. 

For example, by preventing pollutant releases from fires and explosions or reducing pollutant transport, the

characteristics protect the environment as well as human health. The quantitatively-defined levels of protection

incorporated into the TC leachate concentration limits were based on human toxicity considerations; they do not

consider toxicity to non-human receptors. While the exposure levels accepted as protective of human health may be

generally protective of wildlife populations, notable exceptions arise both from the ecotoxicological properties

of some chemicals and from differences between human and non-human receptor exposure patterns.

The question therefore can be asked: To what extent is the TC protective of ecological receptors? As in

the case of human health risks, the TC does not directly protect against risks from chemicals not on the TC list. 

Similarly, it is not clear how protective the existing TC levels are for the various exposure pathways that are

most important for aquatic and terrestrial receptors. In the case of ecological receptors, as is the case for

human health, both direct and indirect exposure pathways may be significant. These issues are addressed in more

detail in Section 3.5 and Chapter 4 of this report.
Page 3-6

3.1.6 Other Risks Associated with Non-Hazardous Industrial Waste Management

In establishing the existing hazardous waste characteristics, the Agency focused exclusively on human

health risks directly associated with local effects of accidents and on chemical contamination of the environment

in the near vicinity of the management units. In Chapter 5 of this study, EPA has taken a broader view, and has

expanded the scope of the risk identification to include risks other than those originally considered, even

indirectly, in establishing the hazardous waste characteristics. These additional categories of risks include

damages to natural resources and contributions to large-scale environmental problems.

Non-hazardous industrial waste management has the potential to adversely affect the value or utility of

natural resources, such as wetlands, groundwater, and air, without posing human health risks. For example,

releases from non-hazardous industrial waste management units have polluted previously usable groundwater with

constituents generally not considered toxic, such as iron, manganese, chloride, and total dissolved solids. The

regulatory criteria violated by these releases, such as Secondary Maximum Concentration Levels (SMCLs) developed

under the Safe Drinking Water Act, are not directly health-related, but relate instead to the aesthetic properties

or usability of the water. Therefore, even though no health risk is predicted, the water is rendered unusable and

the environment is thereby damaged. Similarly, odor from non-hazardous industrial waste management may be seen as

an air resource damage, reducing the quality of life for affected individuals, even in the absence of direct health

effects.

The last category of risks are associated with the possible contribution of non-hazardous industrial

waste management to large-scale environmental problems, including:

Air deposition to the Great Waters;

Damages from airborne particulates;

Global climate change;

Potential damages from endocrine disruptors;

Red tides;

Stratospheric ozone depletion;

Tropospheric ozone and photochemical air pollution; and

Water pollution.

The possible relationship between non-hazardous industrial waste management and these risks is less clear than for

the previously identified risks.

As summarized in Exhibit 3-1, Section 3.1 has presented an intentionally broad inventory of potential

risks to human health and the environment associated with the management of non-hazardous industrial wastes not

currently identified as hazardous. This list provides a catalogue of risks for evaluation against the existing

characteristics in the rest of this chapter and the following chapters.
Page 3-7

Exhibit 3-1. Risks Potentially Associated with Non-Hazardous Industrial Waste Management

Types of Risks By Characteristics Risks Not Intended to be Addressed by Characteristics

RisksIntended to be Addressed

Physical Hazards Burns and injuries to waste Physical injuries to the general public

management and Facilitated transport of organics from solubilization

transportation workers DNAPL/LNAPL generation

from fire, explosions, and

violent reactions

Skin, eye injury from

direct contact with

corrosive substances

(workers)

Facilitated transport of

chemicals (primarily

inorganics) in groundwater

Acute Toxicity Adverse effects from Inhalation of toxic gases and particulates by public

Risks to Humans inhalation of toxic gases Acute health risks from other exposure pathways (direct contact,

and particulates (workers) ingestion of contaminated water or food)

Chronic Toxicity Risks of cancer and non- Chronic health risks to workers

Risks to Humans cancer effects from Chronic risks from exposures to non-TC chemicals (public and

consumption of groundwater workers)

contaminated by TC Chronic risks associated with non-groundwater pathways: 

constituents (public) -- inhalation of volatilized materials and particulates other than

those released from fire or explosion

-- ingestion of surface water contaminated by runoff or groundwater

discharge

-- risks to public from direct contact with waste, contaminated

soil, and in direct pathways (ingestion of contaminated crops,

fish, game)

Risks from specific types of toxins:

-- reproductive toxins

-- endocrine disruptors

Toxic Risks to -- Aquatic toxicity

Nonhuman

Receptors

 Toxicity to terrestrial organisms

 Sediment toxicity

 Bioaccumulation/biomagnification

 Groundwater exposure

Other Risks -- Damages to groundwater, surface water, and air affecting their

usability or quality

Non-hazardous industrial waste management contribution to largescale environmental problems, such as air deposition to the Great

Waters, damages from airborne particulates, global climate change,

potential damages from endocrine disruptors, red tides,

stratospheric ozone depletion, tropospheric ozone and

photochemical air pollution, and water pollution.
Page 3-8

Potential Ignitability Gaps

Excludes DOT Combustible Liquids (liquids with flash point above 140 but below 200 degrees Fahrenheit)

Excludes Aqueous Flammable Liquids (alcohol solutions of concentrations < 24 percent) that are capable of flashing,

but not supporting combustion

References outdated DOT Regulations

No test methods for non-liquids

3.2 Ignitability Characteristic

This section describes potential gaps related to the definition of the RCRA ignitability characteristic

and its test methods. The basic approach taken in identifying potential gaps for ignitability as well as for

corrosivity and reactivity was to review the original 1980 rulemaking record and to compare the characteristic to

approaches taken to controlling similar hazards under other regulatory schemes, including the U.S. Department of

Transportation's (DOT's) hazardous materials regulations, the U.S. Occupational Safety and Health

Administration's (OSHA's) worker health hazards standards, and state hazardous waste management standards.

3.2.1 Definition of Ignitability

The ignitability characteristic is intended to “identify wastes capable of causing fires during routine

transportation, storage and disposal, and wastes capable of exacerbating a fire once started." These risks

include generally recognized fire hazards to waste management and transportation workers, such as burns and

inhalation smoke or fumes, and the potential generation and facilitated transport in air of toxic particulates and

fumes that could harm the general public. According to 40 CFR 261.21, a solid waste exhibits the characteristic of

ignitability if a representative sample of the waste has any of the following properties:

Is a liquid, other than an aqueous solution containing less than 24 percent alcohol by

volume and has flash point less than 60 C (140 F), as determined by: o o

-- A Pensky-Martens Closed Cup Tester, using the test method specified in ASTM

Standard D-93-79 or D-93-80 (incorporated by reference, see § 260.11),

-- A Setaflash Closed Cup Tester, using the test method specified in ASTM standard

D-3278-78 (incorporated by reference, see § 260.11), or

-- An equivalent test method approved by the Administrator under procedures set

forth in §§ 260.20 and 260.21;

Is not a liquid and is capable, under standard temperature and pressure, of causing fire

through friction, absorption of moisture or spontaneous chemical changes and, when

ignited, burns so vigorously and persistently that it creates a hazard;

Is an ignitable compressed gas as defined in 49 CFR 173.300 and as determined by the test

methods described in that regulation or equivalent test methods approved by the

Administrator under §§ 260.20 and 260.21; or

Is an oxidizer as defined in 49 CFR 173.151.

3.2.2 Potential Gaps Related to Definition of Ignitability
 U.S. Environmental Protection Agency, Office of Solid Waste, Background Document: Resource Conservation and Recovery Act, 3

Subtitle C -- Identification and Listing of Hazardous Wastes, Section 261.21-Characteristics of Ignitability, May 2, 1980, p.

10-11.

Page 3-9

Liquids with flash point at or above 140 F not covered. The RCRA ignitability characteristic includes

liquid wastes with flash point less than 60 C (140 F). When promulgating the original characteristic, EPA o o

acknowledged choosing a definition for ignitable liquid wastes that excluded some potential wastes that would meet

the definition of hazardous materials under DOT regulations. The DOT definition of flammable liquid includes

liquids with flash point not more than 60.5 C (141 F), or any material in liquid phase with a flash point at or

above 37.8 C (100 F) that is intentionally heated and offered for transportation or transported at or above its

flash point in a bulk packaging. The DOT definition of combustible liquid includes liquids with flash point above

60.5 C (141 F) and below 93 C (200 F). Thus, the RCRA ignitability characteristic covers wastes that would be

classified as DOT flammable liquids, but not DOT combustible liquids. Consistent with DOT regulations, OSHA

includes such "combustible" liquids in its definition of health hazard, and Rhode Island regulates them as

hazardous wastes.

In a background document supporting the promulgation of the original characteristics, EPA stated that 3

the RCRA ignitability flash point limit of 140 F reflects conditions likely to be encountered during routine waste o

management. In support of this conclusion, the Agency referenced seven studies documenting temperatures and

conditions at waste management units. The information available to the Agency at the time was limited, however. 

Furthermore, two of these studies reported temperatures of greater than 140 F. One study reported temperatures of o

approximately 160 F near the surface of a landfill, noting that aerobic conditions near the surface of landfills o

often result in relatively high temperatures.

Data are still limited regarding whether temperatures greater than 140 F are encountered during non- o

hazardous industrial waste management, in what situations and how frequently this occurs, and what maximum

temperatures are reached (particularly in hotter regions of the nation). One relevant issue is whether

temperatures exceeding 140 F may be encountered during mismanagement (as opposed to routine waste management). o

Examples of possible mismanagement scenarios for ignitable wastes include:

Wastes stored in closed, heat-containing facilities (e.g., metal sheds, upper floor

warehouse spaces, or metal trucks) in hot climates and/or sunlight; and

Wastes mixed in waste management units in a manner that might generate heat through

chemical reactions, especially in the presence of hot climate or sunlight.

No information is readily available regarding the universe of "combustible" industrial wastes currently

being managed as non-hazardous. Nevertheless, some liquid materials with flash points generally in this range can

be identified, as shown in Exhibit 3-2. Examples include certain alcohols, low molecular weight esters, ethylene

glycol ethers, kerosene, jet fuels, certain petroleum byproducts, many "tints and paints," and individual

chemicals including benzaldehyde, benzonitrile, and bromobenzene. If these materials are disposed of or are

present in wastes, the wastes may be combustible, in spite of not being hazardous by the ignitability

characteristic. In addition, mixtures of materials of differing flash points may fall into this category.

Exclusion for aqueous liquids containing less than 24 percent alcohol may warrant reexamination. At the

time of the original rulemaking, some commenters argued that liquid wastes such as wine and some latex paints that

exhibit low flash points because of their alcohol content do not sustain combustion because of the high percentage

of water and therefore should not be designated as characteristically hazardous waste. EPA agreed and excluded

from the ignitability characteristic aqueous solutions containing less than 24 percent of alcohol by volume. A
 45 Federal Register 33108. 4

Page 3-10

similar exclusion is found in DOT regulations. EPA stated that it hoped "to undertake further study to determine

whether another exclusion limit is more appropriate and to evaluate tests which might be capable of identifying

wastes which exhibit this phenomenon." EPA also intended to evaluate possible supplemental test methods to 4

evaluate flammability hazards for these types of wastes.

The exclusion for aqueous liquids containing alcohol has caused confusion during implementation and

enforcement concerning whether it applies only to ethanol or more broadly to all alcohols. The exclusion also

focuses on aqueous alcohol solutions, rather than on the underlying target of liquids with low flash points that do

not sustain combustion. (Tests for sustained combustion are now available: ASTM has methods D-4206 and D-4207.) 

In addition, the rationale that certain liquids should not be considered ignitable if they do not sustain

combustion may not be valid where an excluded aqueous solution could flash and ignite a co-managed non-hazardous

waste that would sustain combustion.
Page 3-11

"Adhesive" Ethylhexaldehyde

Exhibit 3-2

Materials Formerly Classified by DOT as Combustible Liquids

(which generally are not RCRA ignitable)

Source: Suspect Chemicals Handbook, 1988.

n.o.s. = not otherwise specified.

Note: Current DOT Hazardous Materials Table in 49 CFR 172.101 does not distinguish combustible liquids from flammable liquids. 

The above list was taken from a 1987 version of DOT regulations that classified some materials as combustible liquids. This list

is intended to provide examples of materials "that may be combustible (i.e., liquids with 141 F < flash point < 200 F)." o o
 Background Document, supra footnote 2, p. 14. 5

 45 Federal Register 33108. 6

 60 Federal Register 37974, July 25, 1995. 7

Page 3-12

References to DOT regulations are outdated. The ignitability characteristic refers to a DOT definition

of ignitable compressed gas (49 CFR 173.300) that has been withdrawn. Current DOT regulations at 49 CFR 173.115

define flammable gas, which is any material that is a gas at 20 C (68 F) or less and 101.3 kPa (kilopascals equal

to 14.7 pounds per square inch) of pressure. The complete definition includes any material that has a boiling

point of 20 C (68 F) or less at 101.3 kPa (14.7 psi)) that (1) is ignitable at 101.3 kPa (14.7 psi) when in a

mixture of 13 percent or less by volume with air; or (2) has a flammable range at 101.3 kPa (14.7 psi) with air of at

least 12 percent regardless of the lower limit. Likewise, the term oxidizer is no longer defined at 49 CFR 173.151. 

It is now found at 49 CFR 173.127. These out-of-date citations constitute a potential gap because they may cause

regulatory confusion and misinterpretation and thereby may impede efficient and effective compliance and

enforcement.

3.2.3 Potential Gaps Related to Ignitability Test Methods

No test method is specified for non-liquids. The ignitability characteristic does not specify a test

method for non-liquid wastes. In a background document supporting the original rulemaking, EPA stated that nonliquid wastes may present a hazard by virtue of their capacity to ignite and burn as a result of friction, moisture

absorption, or spontaneous reaction under the normal temperatures and pressures encountered in waste management.5

The Agency noted that such wastes are akin to reactive wastes and can directly injure workers or others as a result

of fire, induced explosions, or induced generation of toxic gases at almost any point in the waste management

process. Examples of potential ignitable non-liquid wastes include soils highly contaminated with gasoline or

other ignitable substances and sorbents used to cleanup spills of ignitable substances.

In explaining the final rulemaking, the Agency stated that, although "EPA would have preferred providing

a test method for identifying ignitable solids, it has determined . . . that there are no test methods capable of

accurately identifying the small class of ignitable solids to which its regulation is directed. EPA is presently

working with the Department of Transportation and other organizations to correct this deficiency." Since then, 6

EPA has identified a test method that may be suitable for identifying ignitable solids. Method 1030

("Ignitability of Solids") has been proposed for inclusion in the Third Edition of the EPA test methods manual

"Test Methods for Evaluating Solid Waste, Physical/Chemical Methods," EPA Publication SW-846. The method is 7

appropriate for pastes, granular materials, solids that can be cut into strips, and powdery substances.

3.3 Corrosivity

3.3.1 Definition of Corrosivity

According to 40 CFR 261.22, a solid waste exhibits the characteristic of corrosivity if a representative

sample of the waste has either of the following properties:

Is aqueous and has a pH less than or equal to 2 or greater than or equal to 12.5, as

determined by a pH meter using Method 9040 in "Test Methods for the Evaluation of Solid

Waste, Physical/Chemical Methods," incorporated by reference in § 260.11; or
Page 3-13

Potential Corrosivity Gaps

Excludes corrosive non-liquids

pH limits may not effectively protect against some

types of injury

Corrosion to materials other than steel is not

directly addressed

Solubilization of non-metals (e.g., by organic

solvents) is not addressed

Excludes irritants and sensitizers

pH test methods may not accurately predict hazards

Is a liquid and corrodes steel (SAE 1020) at a rate greater than 6.35 mm (0.250 inch) per

year at a test temperature of 55 C (130 F) as determined by the test method specified in o o

NACE (National Association of Corrosion Engineers) Standard TM-01-69 as standardized in

"Test Methods for the Evaluation of Solid Waste, Physical/Chemical Methods," EPA

Publication SW-846, as incorporated by reference in § 260.11.

The first part of this definition encompasses wastes exhibiting low or high pH, which “can cause harm to

human tissue, promote the migration of toxic contaminants from other wastes, react dangerously with other wastes,

and harm aquatic life.” Specifically, the Agency identified skin and eye damage to transporters who are directly

exposed to the waste as a primary focus of this characteristic. The pH limits also were intended to address the

potential solubilization of heavy metals allowing migration to groundwater, reactions with incompatible wastes

resulting in fires, explosions, generation of flammable or toxic gases, generation of pressure inside vessels, and

the dispersal of toxic vapors, mists, and particulates.

The other part of the corrosivity characteristic relates to the corrosivity of waste to steel containers. 

The Agency identified this aspect of corrosivity as a hazard because “wastes capable of corroding metal can escape

from the containers in which they are segregated and liberate other wastes.” The consequences of liberating

wastes from containers during transportation or storage include harm from direct contact, violent reactions, and

the release of waste components to the environment.

3.3.2 Potential Gaps Related to Definition of Corrosivity

Non-liquids are not covered. The current

RCRA corrosivity characteristic is limited to

liquids. Other regulatory programs, however, also

cover corrosive non-liquids. For example:

DOT regulates corrosive liquids and

solids as hazardous materials;

The OSHA definition of health hazard

includes all corrosives regardless

of physical form; 

The Basel Convention

definitions of hazardous

materials are not limited

to liquids; and

At least four states (California, New Hampshire, Rhode Island, and Washington) include

non-aqueous wastes in their definitions of corrosivity. New Hampshire and Rhode Island

specifically include corrosive gases as well as corrosive solids.

The states that include non-liquids in their corrosivity characteristics specify mixing the non-aqueous

waste with water and then testing for pH. The rationale for this approach is that the waste is likely to come into

contact with water during land-based management. In addition, EPA has developed Method 9045 (Soil and Waste pH),

which can be used to test some corrosive solid wastes. Finally, Method 1120 (Dermal Corrosion) may be applied to

solids, liquids, and emulsions (see additional discussion below under "potential gaps related to corrosivity test

methods").
 U.S. Environmental Protection Agency, Office of Solid Waste, Background Document: Resource Conservation and Recovery Act, 8

Subtitle C-Identification and Listing of Hazardous Wastes, Section 261.22-Characteristic of Corrosivity, May 2, 1980, p. 5.

 Id., pp. 9-10. 9

 45 Federal Register 33109. 10

Page 3-14

pH limits may not cover some hazards. EPA originally proposed pH limits of 12.0 or greater and 3.0 or

less, and a majority of commenters argued that these limits were too stringent. The commenters argued that the

limit of 12.0 or greater would regulate as hazardous many lime-stabilized wastes and sludges, thereby discouraging

use of a valuable treatment technique, and that the pH limit of 3.0 or less would regulate a number of substances

generally thought to be innocuous (e.g., cola drinks) and many industrial wastewaters prior to neutralization. 

EPA agreed with these commenters and promulgated pH limits of 12.5 or greater and 2.0 or less in the 1980 final

rule.

The more stringent proposed pH limits were based on studies of eye tissue damage. These studies indicated

that pH extremes above 11.5 and below 2.5 generally are not tolerated by human corneal tissue. EPA decided that 8

basing pH limits on eye tissue damage was unnecessarily conservative. Thus, eye damage is a hazard not fully

addressed by the corrosivity characteristic.

The corrosivity characteristic also was intended to prevent harm to ecological receptors caused by the

release of hazardous wastes with high- or low-pH. In discussing aquatic life in the original background document,9

EPA noted that the optimum pH range for freshwater fish is 6.5 to 9.0 and that an increase or decrease of 2 pH units

beyond the optimum range causes severe effects. Levels of pH of 11.0 or greater and 3.5 or less are fatal to all

species of fish. EPA also noted that altering surface water pH can reduce the productivity of food organisms

essential to fish and wildlife. The pH limits of the corrosivity characteristic (2.0 and 12.5) are well beyond the

safe range for aquatic life, but wastes presumably would be significantly diluted before the point of exposure to

aquatic life. EPA did not conduct a risk assessment of such potential hazards (e.g., modeling the pathway of waste

released to surface water and exposure to aquatic life) and thus it is not known under what circumstances high- or

low-pH wastes could cause harm to aquatic receptors.

Corrosion of materials other than steel is not directly addressed. In the second part of the corrosivity

characteristic, EPA uses steel corrosion as an indicator of corrosivity. EPA adopted this aspect of corrosivity

because "wastes capable of corroding metal can escape from the containers in which they are segregated and

liberate other wastes." EPA adopted DOT's corrosion standard, noting that the rate at which a waste corrodes a 10

material commonly used in container construction (low carbon steel) is a suitable measure of its hazardousness.
 Ibid, p. 6. 11

 55 Federal Register 11809, March 29, 1990. 12

Page 3-15

The reliance on the steel corrosion rate may create a potential gap if there are plausible mismanagement

scenarios where wastes are stored, transported, or disposed in containers made from materials more easily corroded

than low carbon steel (e.g., plastic by organic solvents) or are disposed in solid waste management units lined

with materials such as clay or synthetics. Also, there may be a potential gap in the characteristic if waste

management scenarios result in conditions where wastes are subject to higher temperatures than the 130 F test o

temperature.

Solubilization of hazardous constituents. The corrosivity characteristic also was intended to address

the potential for high- and low-pH materials to solubilize potentially toxic waste constituents. EPA offers the

example that a drop in pH from 4.0 to 2.0 increases the solubility of red mercury oxide or chromium hydroxide in

water approximately 100 times. The general concern is for inorganic ions that may be converted to more soluble 11

species. This characteristic does not address the potential solubilization of organic constituents by organic

liquids such as solvents, nor does it address the formation of non-aqueous phase liquids (NAPLs) by such

materials. EPA considered including a solvents "override" in the TC characteristic, but did not do so. The 12

solvents override would have caused wastes with high concentrations of solvents to be classified as hazardous on

the basis of potential NAPL formation. The issue of NAPL formation is discussed in more detail in Chapter 5.

Lack of coverage of sensitizers and irritants. At least two types of materials that may pose potential

hazards to humans through direct contact are not included in the corrosivity characteristic or any other

characteristic: irritants and sensitizers. OSHA includes irritants in its definition of health hazard and

defines irritant as a material that is not corrosive, but which causes a reversible inflammatory effect on living

tissue by chemical action at the site of contact. A chemical is a skin irritant if, when tested on the intact skin

of albino rabbits by the methods of 16 CFR 1500.41 for four hours exposure or by other appropriate techniques, it

results in an empirical score of five or more. A chemical is an eye irritant if so determined under the procedure

listed in 16 CFR 1500.42 or other appropriate techniques. (See 29 CFR 1910.1200.)

OSHA also includes sensitizers in its definition of health hazard. A sensitizer is defined as a material

that causes a substantial proportion of exposed people or animals to develop an allergic reaction in normal tissue

after repeated exposure to the chemical. (See 29 CFR 1910.1200.)

This analysis did not identify any specific non-hazardous industrial wastes that are irritants or

sensitizers. Irritants and sensitizers, however, are common categories of materials and these properties are

often identified in laboratory testing of materials. A major issue regarding this potential gap is whether any

irritants and/or sensitizers pose a hazard in wastes that reaches the statutory level of hazard intended to be

covered by RCRA Subtitle C.
 45 Federal Register 33109. 13

Page 3-16

3.3.3 Potential Gaps Related to Corrosivity Test Methods

Use of pH as an indicator has limitations. EPA chose pH as a measure of corrosivity because "wastes

exhibiting low or high pH can cause harm to human tissue, promote the migration of toxic contaminants from other

wastes, react dangerously with other wastes, and harm aquatic life." The ability of some substances to damage 13

human tissue, however, may not be adequately indicated by a pH measurement. Other regulatory and advisory bodies

(e.g., DOT, OSHA, Basel Convention) use criteria based on full thickness destruction of human skin.

Since the original rulemaking in 1980, Method 1120 (Dermal Corrosion) has been developed commercially. 

The dermal corrosion assay system is an in vitro test method which determines the corrosive potential of a

substance toward human skin. It can be used to test liquids (aqueous or non-aqueous), solids (water soluble or

insoluble), and emulsions. Method 1120 is essentially the same method that DOT uses. It replaced previous tests

(e.g., Draize test) that used live animals with a test that uses a proprietary synthetic pig collagen material.

3.4 Reactivity

3.4.1 Definition of Reactivity

The reactivity characteristic is “intended to identify wastes, which because of their extreme instability

and tendency to react violently or explode, pose a problem at all stages of the waste management process.” This

characteristic was intended to reduce physical risks to transportation and disposal workers and to avoid incidents

that could result in the release of toxic constituents into the air consequent to an explosion or violent reaction. 

40 CFR 261.23 states that a solid waste exhibits the characteristic of reactivity if a representative sample of the

waste has any of the following properties:

Is normally unstable and readily undergoes violent change without detonating;

Reacts violently with water;

Forms potentially explosive mixtures with water;

When mixed with water, generates toxic gases, vapor, or fumes in a quantity sufficient

to present a danger to human health or the environment;

Is a cyanide or sulfide bearing waste which, when exposed to pH conditions between 2 and

12.5 can generate toxic gases, vapors or fumes in a quantity sufficient to present a

danger to human health or the environment;

Is capable of detonation or explosive reaction if it is subjected to a strong initiating

source or if heated under confinement;
 45 Federal Register 33109. 14

 45 Federal Register 33110. 15

Page 3-17

Potential Reactivity Gaps

Broad, non-specific definitions

References outdated DOT regulations

No test methods specified

Is readily capable of detonation or explosive decomposition or reaction at standard

temperature and pressure; or

Is a forbidden explosive as defined in 49 CFR 173.51, or a Class A explosive as defined

in 49 CFR 173.53 or a Class B explosive as defined in 49 CFR 173.88.

3.4.2 Potential Gaps Related to Definition of Reactivity

The Definition is broad and lacks specificity. In

discussing the reactivity characteristic in the 1980 final

rule, EPA stated that "the definition was intended to

identify wastes which, because of their extreme instability

and tendency to react violently or explode, pose a problem at

all stages of the waste management process." EPA noted that 14

the reactivity characteristic encompasses a diverse class of

physical properties and effects and overlaps somewhat with the ignitability characteristic.

Some commenters argued that the definition was vague. They advocated using a quantitative definition

accompanied by testing protocol(s). EPA responded that "the prose definition should provide generators with

sufficient guidance to enable them to determine whether their wastes are reactive." EPA argued that most 15

generators whose wastes are dangerous because they are reactive are well aware of this property and such wastes

usually are generated from reactive feedstocks and/or processes producing reactive products or intermediates. 

EPA further stated that problems posed by reactivity appeared to be confined to a fairly narrow category of wastes.

Theoretically, the reactivity characteristic could be clarified and made consistent with other programs

(especially DOT) by developing more specific definitions of general terms such as "normally unstable," "violent

change," "potentially explosive," "reacts violently with water," "readily capable of detonation," and so forth. 

Other programs include more specific definitions. For example, as shown in Exhibit 3-3, DOT has adopted

definitions of spontaneously combustible material and dangerous when wet material, which could be used to clarify

the RCRA characteristic. Specifically, DOT identifies an ignition time and violent reaction rate. Likewise, OSHA

defines pyrophoric, unstable reactive, and water reactive, specifying reactive conditions such as shocks,

pressure, and temperature which define the characteristic. The Basel Convention also defines similar terms.

References to DOT regulations are outdated. Forbidden explosive are no longer defined in 49 CFR 173.51. 

The current DOT regulations define forbidden explosives at 49 CFR 173.54. Other explosives are defined at 49 CFR

173.50. 49 CFR 173.88 no longer exists.
Page 3-18

Exhibit 3-3

Other Definitions of Reactivity

DOT (49 CFR 173.124)

Spontaneously combustible material is a pyrophoric material, that is a liquid or solid that, even in small

quantities and without an external ignition source, can ignite within five minutes after coming in contact with

air.

A self-heating material is a material that, when in contact with air and without an energy supply, is liable to

self-heat.

A dangerous when wet material is a material that, by contact with water, is liable to become spontaneously

flammable or to give off flammable or toxic gas at a rate greater than 1 liter per kilogram of the material, per

hour.

OSHA (29 CFR 1910.1200)

A pyrophoric chemical is a chemical that will ignite spontaneously in air at a temperature of 130 C or below.

An unstable reactive chemical is a chemical that in the pure state, or as produced or transported, will

vigorously polymerize, decompose, condense, or will become self-reactive under conditions of shocks, pressure

or temperature.

A water reactive chemical is a chemical that reacts with water to release a gas that is either flammable or

presents a health hazard.

Basel Convention Characteristic

An explosive is a solid or liquid capable by chemical reaction of producing gas at such a temperature and

pressure and at such speed as to cause damage to the surroundings.

Substances or wastes liable to spontaneous combustion are liable to spontaneous heating under normal

conditions encountered in transport, or to heating upon contact with air, and being then liable to catch on

fire.

Substances or wastes which, in contact with water, emit flammable gases are substances or wastes, which by

interaction with water, are liable to become spontaneously flammable or to give off flammable gases in

dangerous quantities.

Substances or wastes that cause liberation of toxic gases in contact with air or water are substances or wastes

that, by interaction with air or water, are liable to give off toxic gases in dangerous quantities.

Organic peroxides are organic substances or wastes which contain the bivalent O-O structure are thermally

unstable substances which may undergo exothermic self-accelerating decomposition.
 45 Federal Register 33110, May 19, 1980. 16

 55 Federal Register 11801, March 29, 1990. In finalizing the revised toxicity characteristic, however, the Agency used a 17

generic DAF of 100 in a subsurface fate and transport model to set the regulatory levels.

Page 3-19

3.4.3 Potential Gaps Related to Reactivity Test Methods

Reactivity characteristic lacks test method(s). When the Agency promulgated the reactivity

characteristic in 1980, no available tests were identified for use in defining the reactivity characteristic

because:

They were too restrictive and were confined to measuring how one specific aspect of

reactivity correlates with a specific initiating condition or stress.

Testing the reactivity of a sample does not necessarily reflect reactivity of the waste,

because reactivity varies with properties including mass and surface area.

Most available tests required subjective interpretation of results.

Existing methods were not developed for testing wastes.

Although EPA has identified a test method (Method 9010) for reactive sulfide and/or cyanide bearing

wastes, the Agency has not identified suitable test methods to fully define the reactivity characteristic.

3.5 Potential Gaps Associated with the Toxicity Characteristic

3.5.1 Definition of Toxicity Characteristic

The toxicity characteristic was designed by EPA to reduce risks to public health from chronic exposures to

groundwater contamination caused by releases of toxic waste constituents. The Agency found “persuasive evidence

that the contamination of groundwater through the leaching of waste contaminants from land disposed wastes is one

of the most prevalent pathways by which toxic waste constituents migrate to the environment.” The legislative 16

history of RCRA and EPA’s case studies of damages from hazardous waste management were cited as support for

focusing the toxicity characteristic exclusively on groundwater pathway risks.

EPA originally listed 14 contaminants as part of the toxicity characteristic. Subsequently, EPA added

another 26 substances to the list, as shown in Exhibit 3-4. These 40 TC chemicals were selected because:

The chemicals were included on the 40 CFR Part 261 Appendix VIII list of hazardous waste

constituents that have been “shown to have toxic, carcinogenic, mutagenic, or

teratogenic effects,” and

Appropriate chronic toxicity information had been developed and adequate fate and

transport data were available to allow the modeling of groundwater fate and transport

for each constituent.17
Page 3-20

Arsenic 5.0 Hexachlorobenzene 0.013

Exhibit 3-4

TC Constituents and Regulatory Levels (mg/l)

 Source: 40 CFR 261.24.

Thus, EPA found these chemicals to be among those posing the greatest risk to humans from chronic groundwater

exposure.

The remainder of Section 3.5 evaluates the TC in five steps:

Section 3.5.2 examines whether new data on the toxicity and persistence of TC analytes

and updated groundwater transport modeling techniques would result in allowable TC

leachate concentrations different from those established in 1990.

Section 3.5.3 presents screening-level exposure and risk modeling methods and results

that are used to evaluate whether the current TC chemicals could pose risks to human

health and environmental receptors through the inhalation pathway.

Sections 3.5.4 and 3.5.5 evaluate potential risks from TC chemicals to human health

through surface water pathways and indirect pathways, respectively. These risks are

evaluated by comparing toxicity and fate and transport values to defined risk-related

criteria, both singly and in combination, and by reviewing the results of the Agency's

multipathway risk modeling for the analytes that was performed as part of the proposed

Hazardous Waste Identification Rule (HWIR-Waste) development.
Page 3-21

Sections 3.5.6 and 3.5.7 evaluate the potential for acute adverse health effects of

exposures to TC analytes and potential risks to ecological receptors from TC analytes,

respectively. 

3.5.2 Changes in Groundwater Pathway Analysis

This section of the Scoping Study explores two issues related to the current TC regulatory levels: (1)

whether new toxicity data indicate a potential need to revise the regulatory levels; and (2) whether, in light of

recent developments in groundwater modeling techniques, the current dilution and attenuation factor (DAF) value

of 100 still provides a reliable basis for assuring that human health is protected against risks from groundwater

exposures to TC chemicals.

Revisions to MCLs and Toxicity Criteria

The toxicological bases for the establishment of TC analyte regulatory levels were chronic toxicological

and health-based regulatory criteria that were current at the time of promulgation. These included Safe Drinking

Water Act Maximum Contaminant Levels (MCLs), Reference Doses (RfDs), and Risk-Specific Doses (RSDs) based on

ingestion pathway Cancer Slope Factors (CSFs). For almost all of the TC analytes, these values have not changed

since 1990. The few changes have included:

A reduction in the RfD for p-cresol by a factor of ten and the withdrawal of the MCL of 50

ug/l for lead and its replacement with an Action Level of 15 ug/l. For cresol and lead,

the reductions in RfDs and promulgation of Action Levels indicate that the toxicological

evaluation of these chemicals has changed such that the TC regulatory levels may be less

protective than was originally intended. The changes for both of these analytes were an

order of magnitude or less.

The withdrawal of the MCL for silver, with its replacement by an SMCL at the same value. 

This change simply means that the critical toxic effect for silver (argyria, which is

the collection of dark pigment in the skin and mucous membranes) has been downgraded

from a health effect to a cosmetic effect.

In addition, the RfD for pentachlorophenol has been reduced from 2 mg/l to 3x10 mg/l. -2

More importantly, since the TC was revised, the Agency has promulgated a cancer slope

factor for this compound, which is a suspect human carcinogen. Thus, the critical toxic

endpoint has been changed from non-cancer to cancer induction. The promulgation of the

Cancer Slope Factor implies that a much lower TC regulatory level (about 1000 times

lower) would be needed to achieve the same level of protection against cancer risks as

originally intended when the TC was promulgated.
 A detailed discussion of the groundwater modeling approach used by EPA in support of the TC rule can be found at 55 Federal 18

Register 11816, March 29, 1990.

 Ibid at 11827. 19

 A detailed discussion of the EPACMTP model can be found in U.S. Environmental Protection Agency, Office of Solid Waste, 20

EPACMTP Background Document, 1995; and EPACMTP Background Document for Metals, Volume 1: Methodology, 1995.

Page 3-22

Advances in Groundwater Modeling

To develop the existing TC regulatory levels, the Agency used the EPAMCL model to estimate the likely

extent of dilution after the release of waste constituents from waste management units during their transport to

the nearest drinking water wells. These calculations were conducted for municipal solid waste landfills and 18

Subtitle D surface impoundments, taking into account the geochemical properties of the constituents, the size and

configuration of the units, the vadose zone and groundwater regimes beneath the units, and the distribution of

distances in the downgradient direction to the nearest drinking water well. Groundwater regimes were defined

using distributions of transport parameter values typical of conditions throughout the United States. Receptor

wells were assumed to be in the groundwater plume at a distribution of distances derived from a Subtitle D facility

survey. Simulation methods were used to derive estimates of dilution-attenuation factors (DAFs) for each

constituent and each type of waste management unit. After reviewing the results, the Agency elected to calculate

acceptable leachate concentrations (regulatory levels) for each TC analyte using a single DAF value of 100. In 19

other words, the threshold leachate concentration of each analyte above which wastes would be identified as TC

hazardous was set equal to allowable drinking water concentration or other benchmark (10 cancer risk or Hazard -5

Quotient (HQ) = 1.0) for the analytes multiplied by 100.

Since the TC was promulgated, the Agency has continued to use the same general approach to evaluate the

groundwater transport of pollutants in developing RCRA regulations. The exact techniques used in this modeling,

however, have changed significantly. In recent rulemakings, the Agency has used an updated version of the EPAMCL

model, known as EPACMTP, to derive constituent-specific DAFs for a wide range of pollutant releases from hazardous

and non-hazardous waste management units. This model employs many of the same basic transport algorithms as the

EPAMCL, with several important differences, including the following:20

The EPACMTP model uses a detailed metals speciation model (MINTEQA) to estimate leachate

concentrations from wastes of defined ionic composition, whereas the EPAMCL model did

not employ such a model;

The EPACMTP, unlike EPAMCL, can model the adsorbtion to soil and transformation of

organic waste constituents by hydrolysis into more toxic (or less toxic) transformation

products;

The EPACMTP directly simulates the interface between the saturated and vadose zones;

The EPACMTP model can simulate groundwater mounding under management units, whereas the

EPAMCL could not; and

The EPACMTP model provides more flexibility in modeling finite, versus infinite, source

terms.
 U.S. Environmental Protection Agency, Office of Solid Waste, Technical Support Document for the Hazardous Waste 21

Identification Rule: Risk Assessment for Human and Ecological Receptors, August 1995.

 U.S. Environmental Protection Agency, Office of Solid Waste, Regulatory Impact Analysis of the Supplemental Proposed Rule 22

Applying to Phase IV Land Disposal Restrictions to Newly Identified Mineral Processing Wastes, December 1995.

Page 3-23

Recent applications of the model also used somewhat different assumptions regarding waste and facility

characteristics, hydrogeological regimes, climatology, and receptor locations than those used in the development

of the TC. Therefore, it is not possible, except in a very general way, to simply compare the DAF value used in

establishing the TC allowable leachate concentrations with the constituent-specific DAF values for the same

constituents derived in the subsequent analyses. In addition, DAF values derived for metals using the EPACMTP

vary with the initial concentration of the constituent in the waste, because the model incorporates saturable

binding and transport phenomena. In contrast, the DAFs derived using the EPAMCL model are concentration-invariant

under most conditions.

Recently, EPA has employed the EPACMTP model in two major regulatory development efforts. 

EPA applied the model in its development of proposed risk-based exit levels for the

Proposed Hazardous Waste Identification Rule for Process Waste (HWIR-Waste). In that 21

analysis, EPACMTP was used to back-calculate concentrations of constituents in wastes

and in waste leachate corresponding to specific risk levels through groundwater

exposures. The Agency is currently revising the proposed HWIR-Waste exit level

groundwater risk modeling methods in response to comments from the Science Advisory

Board and from other technical reviewers. Thus, the results of this modeling presented

in this Scoping Study should be regarded as preliminary.

In the Phase IV LDR regulatory development effort for mineral processing wastes, the

model was used to derive constituent-specific DAFs for mineral processing wastes

disposed of in surface impoundments and waste piles. The DAFs were then used to derive 22

groundwater pathway risk estimates for exposure to waste constituents.

The results of these analyses have been used to evaluate the extent to which changes in modeling

techniques may have affected the assessment of groundwater fate and transport relative to the assessment used to

derive the TC regulatory concentrations. As noted previously, a simple comparison of DAF values and/or calculated

risk levels from the different modeling efforts is not possible without further analysis since the more recent

modeling employs different groundwater transport models and different assumptions regarding facility

characteristics, groundwater regimes, and receptor locations. In the case of the mineral processing risk

assessment, for example, DAF values were derived specifically for facility sizes representative of the mineral

processing industry, rather than Subtitle D management units. In addition, groundwater modeling was performed

using climatologic data primarily from drier regions where many mineral processing facilities are located. While

Subtitle D facilities were used to calculate releases for the HWIR-Waste proposal, the receptor wells were assumed

to be distributed uniformly in the downgradient direction, instead of being confined to the plume. More

importantly, the proposed exit levels were derived using a carcinogenic risk target of 10 , rather than 10 , and -6 -5

the 90th percentile, rather than the 85th percentile, estimates of risk were used. Using the 90th instead of 85th

percentile of the risk output results in estimating higher risks for a given receptor for a given constituent

concentration and in more stringent (lower) exit levels. Thus, the proposed HWIR-Waste risk calculations,

especially for carcinogens, are substantially more conservative in several important respects than those used to

derive the TC regulatory levels.
 In one of these cases (for endrin), however, the limiting risk, is ecological, rather than human health. 23

Page 3-24

In the mineral processing risk assessment, DAF values were derived for eight of the TC analyte metals. For

waste piles, the DAF values for the majority of the TC metals were considerably higher than 100, the highest value

being 1x10 for lead. Barium, with a DAF value of 54, was the only metal for which the mineral processing waste 30

pile DAF was less than the value of 100 used in the derivation of the TC regulatory concentrations. These results

imply that the DAF value of 100 used in the TC derivation remains conservative for most metals when compared to

values derived for this population of facilities. 

The situation is different, however, if the DAF values derived for mineral processing surface

impoundments are used as a basis for comparison. In this case, the majority of the DAF values for the TC metals

were less than 100. This finding suggests that the DAF value of 100 used to derive the TC regulatory levels may not

provide adequate protection against groundwater risks from surface impoundments, which are the most frequent

management type employed for non-hazardous industrial wastes.

The large difference in DAF values for the two types of management units can be explained partly in terms

of the comparative aridity of the locations for which DAFs were calculated. Where little moisture was available to

drive transport from the waste piles through the vadose zone, DAF values tended to be high. In contrast, the

surface impoundments provided a water supply that drove transport through the vadose zone into groundwater. The

extent to which this effect would be seen in moister regions of the country is not clear.

The HWIR-Waste proposed groundwater exit level calculations for the TC analytes are summarized in Exhibit

3-5, and compared to the TC regulatory levels. The majority of the exit levels are considerably lower (more

stringent) than the corresponding TC regulatory levels. In 4 cases, the TC levels are comparable to or less than

the exit level. For 9 analytes, the ratio of the TC regulatory level to the exit level is between 1 and 10. For 12 23

analytes, this ratio is between 10 and 100; for 5 analytes, the ratio is between 100 and 1,000; and for 6 analytes,

the ratio is greater than 1,000. 

This distribution confirms that, generally, the assumptions and modeling approaches used to derive the

HWIR-Waste proposed exit levels lead to somewhat more conservative or more protective results than those used to

derive the TC regulatory levels. This conclusion holds true, even taking into account that the cancer risk target

is 10-fold lower for setting some of the proposed exit levels than was used for setting the TC levels. For all but

a few of the carcinogens among the TC analytes, the proposed exit levels are far more than 10 times lower than the

corresponding TC regulatory levels. Thus, some other factors account for a significant proportion of the

conservatism in these calculations.
Page 3-25

Exhibit 3-5

Comparison of TC Regulatory Concentrations

and HWIR-Waste Proposed Exit/Leach Levels

Analyte mg/l Level, mg/l Level (mg/l) Level

Chronic Toxicity HWIR-Waste Regulatory Level

Reference Level, TC Regulatory Groundwater Exit to Exit/Leach

a a b

Ratio of

Arsenic 0.05 5 0.000148 33784

Barium 1 100 15.5 6.5

Benzene 0.005 0.5 0.0054 92.6

Cadmium 0.01 1 0.11 9.1

Carbon tetrachloride 0.005 0.5 0.00161 311

Chlordane 0.0003 0.03 0.000163 184

Chlorobenzene 1 100 1.33 75.2

Chloroform 0.06 6 0.017 353

Chromium 0.05 5 0.476 10.5

Cresol, m- 2 200 3.2 62.5

Cresol, o- 2 200 3.2 62.5

Cresol, p- 2 200 0.32 625

Dichlorobenzene, 1,4- 0.075 7.5 0.0108 694

Dichloroethane, 1,2- 0.005 0.5 0.00006 8333

Dichloroethylene, 1,1- 0.007 0.7 0.00018 3889

2,4-D 0.1 10 0.6 16.7

Dinitrotoluene, 2,4- 0.0005 0.13 0.112 1.2

Endrin 0.0002 0.02 32 0.000625

Heptachlor 0.00008 0.008 No value 30

Heptachlor epoxide 0.00008 0.008 0.45 0.0178

Hexachloro-1,3-butadiene 0.005 0.5 0.00691 72.4

Hexachlorobenzene 0.0002 0.13 0.000113 1150

Lindane 0.004 0.4 0.693 0.577

Hexachloroethane 0.03 3 0.033 90.9

Lead 0.05 5 11.6 0.4
Page 3-26

Exhibit 3-5 (continued)

Comparison of TC Regulatory Concentrations

and HWIR-Waste Proposed Exit/Leach Levels

Analyte MCL or HBL Level, mg/l ExitLevel (mg/l) Level a

TC Regulatory HWIR-Waste Lowest to Exit/Leach

a b

Ratio of

Regulatory Level

Mercury 0.002 0.2 0.138 1.4

Methoxychlor 0.1 10 No value --

Methyl ethyl ketone 2 200 30 6.7

Nitrobenzene 0.02 2 0.032 62.5

Pentachlorophenol 1 100 0.00041 243902

Pyridine 0.04 5 0.06 83.3

Selenium 0.01 1 0.357 2.8

Silver 0.05 5 No value --

Tetrachloroethylene 0.007 0.7 0.68 1.0

Toxaphene 0.005 0.5 0.11 4.5

Trichloroethylene 0.005 0.5 0.0128 39

Trichlorophenol, 2,4,5- 4 400 4.2 95.2

Trichlorophenol, 2,4,6- 0.02 2 0.0152 132

Silvex 0.01 1 0.48 2.1

Vinyl chloride 0.002 0.2 0.00006 3333

Notes:

55 Federal Register 11804, March 29, 1990. a

60 Federal Register 66424-66432, December 21, 1995. b

Some of this conservatism may be due to differences in modeling assumptions, rather than modifications in

modeling techniques. For example:

The HWIR-Waste proposed exit levels were derived to be protective of 90th percentile

receptors, while the TC levels were set to be protective of 85th percentile receptors. 

As shown in Exhibit 3-5, some HWIR-Waste proposed exit levels were driven by exposure

pathways other than groundwater. 

The proposed HWIR-Waste exit levels and the TC regulatory levels were designed for

different purposes. The TC levels are designed to provide a method for identifying
Page 3-27

wastes that would otherwise be non-hazardous, while the proposed HWIR-Waste exit levels

would relieve wastes previously identified as hazardous from stringent regulatory

control. 

These issues are discussed in more detail in Sections 3.5.3 and 3.5.4. Other differences in modeling assumptions,

such as the retention of constituents in waste management (loss terms) in TC modeling only and the differences in

the assumed location of wells relative to the contamination source, influence the results in the other direction.

Summary. Based on the preceding analyses, only general conclusions can be drawn about whether there are

any significant gaps in the TC associated with the specific regulatory levels set for individual constituents. 

The wide range in the mineral processing DAF values illustrates the high degree of variability associated with

specific groundwater modeling assumptions, and does not necessarily indicate whether the DAFs should be

considered less or more protective than when they were originally derived. The HWIR-Waste proposed exit level

calculations, on the other hand, suggest that the application of more recent modeling techniques might result in

more conservative transport calculations. Some, but not all, of this greater level of protectiveness reflects a

policy decision by the Agency regarding what proportion of receptors should be protected to the target risk level. 

In addition, advances in modeling techniques and differences in specific input assumptions also affect the

differences in the apparent levels of protectiveness.

3.5.3 Potential Inhalation Pathway Risks Associated with TC Analytes

This section investigates the general level of protectiveness of the allowable TC concentrations against

direct inhalation, a risk that the TC was not specifically intended to protect against. EPA analyzed this issue by

performing screening-level risk calculations for long-term air releases of the TC constituents from Subtitle D

facilities. EPA used the CHEMDAT8 model using facility characteristic parameters for surface impoundments and

land application units (LAUs). Release estimates for all of the organic TC analytes were developed for two

scenarios.

In the first scenario, releases were estimated from the same “high-end” surface

impoundments and LAUs that were modeled in the proposed HWIR-Waste exit level modeling.

The second scenario modeled releases from the "central tendency" impoundments and LAUs,

which were considerable smaller and shallower than the high-end units.

In both release scenarios, the concentrations of the organic TC analytes were assumed to be at the TC regulatory

level for liquid wastes in surface impoundments and at 20 times the TC levels for nonwastewaters in land

application units. The latter assumption roughly estimates the maximum concentration of the TC analyte that could

be present without the waste being hazardous, assuming efficient leaching using the TCLP. For analytes that do not

leach well, this approach may underestimate exposure concentrations and risks associated with air releases from

non-hazardous industrial wastes, since nonwastewaters with high concentrations of constituents would not be

identified as hazardous by the TCLP. Average releases to air were calculated for an assumed 40-year facility lifespan under both scenarios. The basic approach and input assumptions used in the modeling are summarized in

Exhibit 3-6.

The organic TC analytes for which releases were modeled vary widely in molecular weight, vapor pressure,

Henry’s Law constant, and other physical properties that affect releases to air. Thus, the extent of release of

these chemicals to air from land disposal facilities might be expected to differ widely. This is true to some

extent; but, as can be seen in Exhibit 3-7, the estimated release of these compounds from land application units

and surface impoundments over the expected facility life-span varies only moderately. In the case of the high-end
 Release from surface impoundments were estimated on an annual basis, rather than on a facility life-time basis because 24

these units receive a constant and continuous flow of wastes throughout the facility life, with liquid flowing out of the unit

after an assumed dwell time. In contrast, once a waste is added to an LAU, it is assumed to remain in the facility to volatilize

throughout the facility life-span.

Page 3-28

land application units, between approximately 7 percent and 100 percent of the chemicals entering the units are

released to the air over the facility life. The average proportion of the analytes released from these units was

81.6 percent, and the calculated releases were greater than 95 percent for two-thirds of the organic TC analytes. 

The results were similar for the central tendency LAU. Releases ranged from 27 to 100 percent of the

analytes, and the average proportion released was 96.3 percent. The explanation for the predicted higher

proportional releases from the central tendency LAU is not clear, but may be related to the shallower tilling depth

assumed for the central tendency unit (0.2 compared to 0.3 meters).

The proportions of the TC analytes released from surface impoundments are shown in the final two columns

of Exhibit 3-7. The releases ranged from 6 to 77 percent of the applied total per year for the high-end

impoundment, with an average release of 55.5 percent per year. Proportionate releases were again higher from the 24

central tendency unit, ranging from 15 percent to 88 percent, with an average of 71.2 percent released annually. 

Similar to the situation for the LAUs, the higher proportional releases from the central tendency unit may be due

to its considerably shallower depth (2 meters) compared to the high-end unit (7 meters).

The limited impact of a chemical's Henry's Law constant on air releases is somewhat surprising in light of

the broad spectrum of solubility and vapor pressure reflected in the chemicals modeled. Perhaps it can best be

understood as indicating that, in the long run (a year or more), a high proportion of any of these organic chemicals

placed in uncovered land management units will be released to the air, provided other removal pathways are not

important. In actual practice, some land application units are covered to some extent, and other removal

processes, such as leaching, biological and chemical degradation, and binding to soil or sediment, compete to

reduce air emissions significantly.

EPA calculated chronic risks from inhalation pathway exposures for all organic TC analytes. To calculate

exposure concentrations, EPA multiplied release estimates by the long-term fenceline dispersion coefficients used

in the proposed HWIR-Waste exit level calculations for the high-end and central tendency surface impoundments and

LAU releases. The fenceline dispersion coefficients are used to represent the nearest credible residential

exposure locations, in keeping with the proposed

HWIR-Waste risk methodology. Exposure durations are assumed to be 30 years in the high-end exposure release and

exposure scenario, and 9 years in the central tendency scenario.
Page 3-29

Modeling Procedures

Estimate release proportions at TC regulatory concentrations

Estimate exposure concentrations using fenceline dispersion coefficients from HWIR-Waste modela

Estimate risks using IRIS and HEAST toxicity values (RfCs and Unit Risk values)

Subtitle D Surface Impoundment from Proposed HWIR-Waste Risk Analysis

HIGH-END CENTRAL TENDENCY

40,000 square meters 2,000 square meters

40-year lifespan 40-year lifespan

Depth 7 meters Depth 2 meters

"Generic" Land Application Unit from Proposed HWIR-Waste Risk Analysis

HIGH-END CENTRAL TENDENCY

900,000 square meters 61,000 square meters

40-year lifespan 40-year lifespan

Tilling depth 0.3 meters Tilling depth 0.2 meters

Long-Term Release Values

Estimated over facility life using CHEMDAT8 model

Modeled at TC concentrations for surface impoundments

Modeled at 20 times TC concentrations for land application units

Assumed persistence in management units (except vinyl chloride)

Chronic Exposure Durations

High-end exposure duration = 30 years

Central tendency exposure duration = 9 years

Chemicals Modeled 

All organic TC analytes

Differ by seven orders of magnitude in Henry's Law constant

Have molecular weight from 30 to 410

Are rapidly degrading to very persistent

 

 Technical Support document for the Hazardous Waste Identification Rule: Risk Assessment for Human and Ecological a

Receptors, US. Environmental Protection Agency, Office of Solid Waste, August 1995.

Exhibit 3-6

Summary of Inhalation Pathway Screening Methods,

Input Data, and Models Used for Bounding Risk Analysis
Page 3-30

Exhibit 3-7

Emission Fraction for Air Releases of Volatile TC Analytes

TC Analyte kH Tendency High-End Tendency High-End

Fraction Emitted From:

Land Application Unit Surface Impoundment

Central Central

Benzene 5.5x10 0.9984 0.9984 0.8661 0.7451 -3

Carbon tetrachloride 2.9x10 0.9984 0.9984 0.8578 0.7318 -2

Chlordane 6.7x10 0.9984 0.6301 0.6649 0.4413 -5

Chlorobenzene 4.4x10 0.9984 0.9984 0.8564 0.7294 -3

Chloroform 4.0x10 0.9984 0.9984 0.8676 0.7475 -3

m-Cresol 8.8x10 0.8228 0.2225 0.2093 0.0858 -7

o-Cresol 1.6x10 0.9749 0.3384 0.3651 0.1713 -6

p-Cresol 8.2x10 0.8249 0.2233 0.2105 0.0864 -7

Cresol -- 0.9678 0.3256 0.3550 0.1648

2,4-D 4.5x10 0.9984 0.6866 0.6970 0.4722 -6

1,4 Dichlorobenzene 2.8x10 0.9984 0.9984 0.8483 0.7163 -3

1,2 Dichloroethane 1.3x10 0.9984 0.9984 0.8659 0.7443 -3

1,1 Dichloroethylene 2.5x10 0.9984 0.9984 0.8769 0.7631 -2

2,4 Dinitrotoluene 1.5x10 0.9984 0.9417 0.7280 0.5151 -7

Endrin 1.2x10 0.2696 0.0674 0.1466 0.0575 -6

Heptachlor 5.9x10 0.9984 0.9984 0.8160 0.6662 -4

Heptachlor epoxide 8.3x10 0.9983 0.5730 0.6558 0.4287 -6

Hexachlorobenzene 7.5x10 0.9984 0.9984 0.8211 0.6744 -4

Hexachloro-1,3-butadiene 2.4x10 0.9984 0.9984 0.8261 0.6824 -2

Hexachloroethane 3.6x10 0.9984 0.9984 0.8335 0.6928 -3

Lindane 3.4x10 0.9984 0.9984 0.8246 0.6793 -6

Methoxychlor 6.3x10 0.9984 0.9979 0.7759 0.6038 -6

Methyl ethyl ketone 3.6x10 0.9984 0.9984 0.8526 0.7174 -5

Nitrobenzene 2.1x10 0.9984 0.9689 0.7851 0.5981 -5

Pentachlorophenol 1.4x10 0.9984 0.9983 0.8021 0.6379 -5

Pyridine 7.0x10 0.9984 0.9822 0.7827 0.5975 -3

Tetrachloroethylene 1.7x10 0.9984 0.9984 0.8519 0.7224 -2

Toxaphene 3.4x10 0.9984 0.9984 0.7891 0.6282 -6

Trichloroethylene 1.1x10 0.9984 0.9984 0.8604 0.7359 -2

2,4,5 Trichlorophenol 4.4x10 0.9979 0.4889 0.5733 0.3339 -6

2,4,6 Trichlorophenol 4.1x10 0.9984 0.7077 0.6830 0.4571 -6

2,4,5-TP (Silvex) 1.3x10 0.9984 0.9984 0.8203 0.6735 -8

Vinyl chloride 8.4x10 0.9984 0.9984 0.8829 0.7733 -2
 The risks are greater from the high-end surface impoundment than from the central tendency surface impoundment, despite the 25

lower proportionate releases from the former units, because the total mass disposed in the high-end unit and the total mass

released are much greater. This result also occurs for the LAUs.

Page 3-31

Exhibit 3-8 summarizes the results of the screening-level risk estimation for the TC analytes having

inhalation pathway toxicity values in IRIS or HEAST (as discussed below). The first eight columns of the results

indicate whether the estimated lifetime cancer risk associated with managing the analytes at the TC (or the TC

multiplied by 20) concentrations in the various management units would be greater than 10 or if the inhalation -5

pathway hazard quotient (HQ) would exceed 1.0. These risk threshold values are the same as those used in

developing the TC analyte concentrations for groundwater exposures. For the 16 TC analytes with IRIS Unit Risk

values, inhalation pathway cancer risks greater than 10-5 are not predicted for any of the TC analytes released from

the central tendency surface impoundment. In contrast, cancer risks above 10 are predicted for 12 of these -5

analytes released from the high-end impoundment. None of these analytes released from the central tendency LAU 25

would result in an inhalation pathway risk greater than 10 . Releases of four analytes (chloroform, 1,4- -5

dichlorobenzene, 1,1-dichloroethylene, hexachlorobenzene, and toxaphene) from the high-end LAU would result in

risks above this level.

Of the four TC organics with inhalation RfCs, hazard quotients greater than 1.0 were calculated for three

analytes (chlorobenzene, methyl ethyl ketone, and nitrobenzene) released from the central tendency surface

impoundment. When releases are modeled from high-end impoundments, the one additional chemical (1,4-

dichlorobenzene) also has an HQ greater than 1.0. Exactly the same pattern is seen for LAUs.

These results indicate that, under assumptions of no degradation or release to other pathways, the cancer

risks and non-cancer hazard indices associated with management of some of the organic TC analytes may be above

levels of concern previously used in amending the TC.

These risks may be overestimated if significant amounts of pollutants in waste are released through other

pathways or are degraded biologically or chemically. For this reason, EPA used the proposed HWIR-Waste database

to identify the TC analytes that are persistent in soil or water. As shown in the last two columns of Exhibit 3-8,

most of the organic analytes that exceed the air risk targets under the assumption of no degradation are, in fact,

not very persistent in either soil or water. Using a cutoff value for degradation rate constants of 0.5 year ,

-1

which corresponds to a half-life in soil or water of about 17 months, only 3 of the organic TC analytes are expected

to be very persistent. The relatively short half-lives in water or soil may reduce the potential concern for

inhalation pathway risks associated with the other TC analytes to the same extent. These results illustrate the

need for more detailed, site-specific modeling of all of the transport and degradation processes.

Risks were calculated in this analysis for only those TC analytes having inhalation pathway toxicity

values (Reference Concentrations or Unit Risk values) in IRIS. If instead inhalation pathway toxicity values were

derived for the rest of the TC analytes from ingestion pathway values and used in similar risk calculations, the

number of chemicals for which cancer risks and particularly non-cancer risks would exceed levels of regulatory

concern would be much higher. These results have not been included in Exhibit 3-8 because EPA considers the level

of uncertainty associated with such procedures to be unacceptably high.
Page 3-32

Exhibit 3-8. Inhalation Pathway Risks for TC Analytes and Their Dependence on Fate and Transport Properties

TC Analyte

Cancer Risk Exceeds 10-5 HQ Exceeds 1.0

Persistent

in Watera

Persistent

in Soil

Surface Impoundment Landfill Surface Impoundment Landfill

Central Tendency High-End Central Tendency High-End Central Tendency High-End Central Tendency High-End

Benzene -- -- -- -- ND ND ND ND -- -- Carbon tetrachloride -- 1.50E-04 -- -- ND ND ND ND -- -- Chlordane -- 1.34E-04 -- -- ND ND ND ND X* X*Chlorobenzene ND ND ND ND 2.55E+03 9.99E+04 5.74E+02 2.06E+04 -- -- Chloroform -- 2.82E-03 -- 5.69E-04 ND ND ND ND -- -- 1,4 Dichlorobenzene ND ND ND ND -- 1.84E+02 -- 3.87E+01 -- -- 1,2 Dichloroethane -- 2.65E-04 -- ND ND ND ND ND -- -- 1,1 Dichloroethylene -- 7.31E-04 -- 1.44E-04 ND ND ND ND -- -- Heptachlor -- 1.90E-04 -- -- ND ND ND ND -- -- Heptachlor epoxide -- 2.44E-04 -- -- ND ND ND ND X XHexachlorobenzene -- 1.10E-03 -- 2.47E-04 ND ND ND ND X XHexachloro-1,3-butadiene -- 2.06E-04 -- -- ND ND ND ND -- -- Hexachloroethane -- 2.28E-04 -- -- ND ND ND ND -- -- Methyl ethyl ketone ND ND ND ND 1.02E+02 3.93E+03 2.30E+01 8.25E+02 -- -- Nitrobenzene ND ND ND ND 4.67E+02 1.64E+04 1.15E+02 4.00E+03 -- -- Tetrachloroethylene -- -- -- -- ND ND ND ND -- -- Toxaphene -- 2.75E-03 -- 6.60E-04 ND ND ND ND ND NDTrichloroethylene -- -- -- -- ND ND ND ND -- -- 2,4,6 Trichlorophenol -- -- -- -- ND ND ND ND -- -- Vinyl chloride -- 3.56E-04 -- -- ND ND ND ND -- -- Notes: Degradation rate constant for soil or water less than 0.5 yr. a -1

 * For surface impoundments only; does not exceed at landfills. X = Yes. -- = Risk or hazard is below threshold.ND = No Data.
 Such releases are likely to be controlled by permit requirements for surface water discharges and through facility design 26

regulations. 

Page 3-33

Evaluation of the proposed HWIR-Waste exit level calculations for the TC analytes confirms the potential

concern for nongroundwater pathways. For some of the TC analytes, the HWIR-Waste proposed exit level calculations

indicated that non-groundwater pathways are significant. Findings include the following:

For 9 of the TC analytes, pathways other than human groundwater exposure drove the

establishment of proposed exit levels.

For six of the analytes, ingestion of contaminated milk or vegetables was the highestrisk exposure pathways.

For one of the pollutants, the driving non-groundwater exposure pathway was direct

inhalation.

For two analytes, ecological risks rather than health risks drove the derivation of

proposed exit levels.

In all of these cases, the initial release was to air through volatilization. These indirect pathway risks will be

discussed in more detail in the following sections.

3.5.4 Potential Risks from Surface Water Exposures

This section investigates the general level of protectiveness of the TC regulatory levels against surface

water exposures, a risk that the TC was not specifically intended to address. Waste constituents could be released

to surface water from land management units through several mechanisms:

Discharge of groundwater contaminated by leachate from waste management units;

Transport of waste constituents to surface water bodies by runoff and overland transport

of wastes released from the management unit;

Direct releases through overland runoff of liquid wastes from surface impoundments;26

and

Volatilization of constituents from land-based units, followed by deposition onto

surface water or onto soil that eventually finds its way into surface water bodies.

The surface water exposure pathways of potential significance for humans include direct consumptive use

(i.e., ingestion and dermal contact with domestic water) and dermal contact and incidental ingestion of the

surface water associated with recreational exposures. If the contaminants are persistent in sediment, dermal

contact and incidental ingestion of small amounts of sediment also are possible exposure pathways.

All of these release and exposure pathways have been analyzed in the development of hazardous waste

management regulations and in other contexts. The experience gained in these exercises has led the Agency to a

number of general conclusions regarding the importance of surface water exposures for human health risks:
 Preliminary Report on Factors Important to Identifying Risk-Based Entry Characteristics: Analysis of Hazardous Waste 27

Identification Risk Models, Ogden Environmental and Engineering Services, August 1996. 

Page 3-34

For common waste management practices, surface water exposure cannot be automatically

ruled out as insignificant in comparison to groundwater, inhalation, and other indirect

pathways.

The significance of surface water releases depends heavily on the management practices

employed by a facility and the specific interactions between surface water and

groundwater at the facility.

Generally, groundwater discharge significantly affects surface water quality only

where groundwater constitutes a significant proportion of the total surface water in a

water body. This pathway may be important for very large management units that generate

large amounts of leachate, but usually significant surface water quality impacts are

limited to relatively small streams adjacent to management units and to on-site or

adjacent ponds derived mainly from leachate.

Exposure to volatile contaminants in surface water is generally limited because these

contaminants are depleted rapidly from surface water through volatilization. Air

releases from surface water may themselves be significant from a health standpoint. 

Usually, however, volatilization from the management unit itself dominates, unless the

unit is covered.

Incidental ingestion and dermal contact with contaminated sediment tend not to be

significant exposure pathways for humans, because of their infrequency and the

relatively small amounts of contaminated sediment contacted (but see below).

Indirect pathway exposures may be of concern, however. The contaminants that persist in

sediment and have a high capacity to bioaccumulate and bioconcentrate are often the most

significant contributors to human health risks. This capacity may overcome the high

dilution factors often associated with releases to surface water. These persistent

pollutants most often reach human receptors through the consumption of contaminated

fish or shellfish. 

In evaluating the potential risks associated with proposed HWIR-Waste chemicals, EPA identified

contaminants for which surface water pathways were of potential concern. Whether or not the surface water pathway

was a concern depended on the waste treatment scenario. For wastewaters managed in surface impoundments, surface

water was not a human health risk for any of the TC analytes. All of the proposed exit levels driving nongroundwater pathways for humans were associated with volatilization followed by deposition on soil and did not

involve surface water. For nonwastewaters disposed in land application units and waste piles, however, more than

50 percent of the proposed exit levels for the HWIR-Waste constituents are driven by pathways involving surface

water exposures. The driving (highest-risk) pathways were approximately equally divided among the contaminants 27

between overland runoff followed by fish uptake, and overland runoff followed by surface water ingestion. These

results must be interpreted cautiously. The analysis of the proposed HWIR-Waste exit levels cited above gives

only a comparative, not an absolute, indication of the importance of the surface water exposure pathways for waste

piles and land application units. The proposed exit levels calculated for these types of units are generally

higher than those associated with surface impoundments, for example, indicating that the magnitude of the risks
 The Koc is the organic carbon binding coefficient; the Kd is the soil-water dissociation constant. 28

Page 3-35

from wastes piles and land application units are, in general, lower than those associated with surface

impoundments.

Summary. The preceding analysis has explored the possibility that significant risks to health or the

environment may be associated with exposures through surface water pathways. While a number of theoretical

arguments suggest that such releases might be important under only a relatively narrow range of conditions, the

proposed HWIR-waste modeling results indicate that these pathways may well be significant for some TC analytes

disposed as non-hazardous industrial wastes. The possibility that the surface water releases and exposures

represent a potential gap in the TC, especially for persistent and bioaccumulative chemicals, cannot be ruled out.

3.5.5 Potential Indirect Pathway Risks from TC Analytes

"Indirect" pathways are any pathways involving more than one environmental medium (e.g., groundwater,

air, surface water, soil, sediment, and biota) between the release and the exposed receptor. The initial release

may be to any medium. Indirect exposure pathways often, but not always, involve uptake of environmental

contaminants by living organisms, which, in turn, are consumed by human or other receptors. Some of the pathways

discussed in the previous sections, such as groundwater releases to surface water, are, strictly speaking,

indirect. This section, however, emphasizes pathways involving potential long-range transport of persistent

pollutants and pathways involving biota (crops, fish, or livestock) prior to human exposures.

Persistence, properties facilitating physical transport, and the potential to bioaccumulate in the

environment are critical in the indirect pathways, and the physical/chemical and environmental fate properties of

constituents significantly determine their movement through such pathways. Exhibit 3-9 summarizes some important

physical, chemical, and environmental fate properties of the TC analytes relating to persistence, partitioning

behavior between environmental media, and bioaccumulation. For each parameter, the exhibit compares each

constituent's value to a criterion or cutoff value that roughly indicates whether the parameter will strongly

influence the transport and partitioning of the chemical in the environment in a multipathway analysis. The

derivation of these criteria are discussed in more detail in Section 4.3.2.

The first column identifies TC analytes with a high Koc (high Kd for metals), generally indicating a 28

propensity to bind to soils. A high value means that chemicals will leach only slowly to soil, but would bind to

particulates if they were released through runoff or into the air. Essentially all of the chemicals with Koc

values above 10,000 are pesticides. In addition, the majority of the TC metals would be expected to bind to some

extent to particulates.
Page 3-36

Exhibit 3-9

Major Fate and Transport Parameters for TC Analytes

TC Analyte

Koc/Kd > Constant > 10 in Air RateConstant Plants > 3.5 Factor > FishBCF/BAF >

 atm-m /mol > 0.15 yr. < 0.5/yr. (ug/g)/(ug/g) 7.8x10 day/kg 1000 l/kg

Henry's Law Half-life Degradation for Forage Biotransfer

-

10,000 ml/g 5 3

Soil/Water Plant-SoilBFC Beef

-4

1,1-Dichloroethene

1,2-Dichloroethane

1,4-Dichlorobenzene

2,4,5-TP (Silvex)

2,4,5-Trichlorophenol

2,4,6-Trichlorophenol

2,4-D

2,4-Dinitrotoluene

Arsenic

Barium

Benzene

Cadmium

Carbon tetrachloride

Chlordane

Chlorobenzene

Chloroform

Chromium

Cresol, mCresol, oCresol, pEndrin

Heptachlor

Heptachlor epoxide

Hexachloro-1,3-butadiene

Hexachlorobenzene

Hexachloroethane

Lead

Lindane

Mercury

Methoxychlor

Methyl ethyl ketone

Nitrobenzene

Pentachlorophenol

Pyridine

Selenium

Silver

Tetrachloroethylene

Toxaphene

Trichloroethylene

Vinyl chloride
 As noted previously, kH is the ratio of a chemical's vapor pressure to its water solubility. 29

Page 3-37

The next column on Exhibit 3-9 shows the Henry's Law constants (kH) for the TC analytes, with values 29

above 10 generally indicating a moderate to high capacity to volatilize from soil-water systems, which may be the -5

first step in an indirect exposure pathway. About half (19) of the TC analytes have kH values above 10 . As -5

discussed in Section 3.5.3, variations in Henry's Law constants did not strongly effect the predicted long-term

release of the TC analytes from surface impoundments and waste piles. Short-term releases, however, may be much

more dependent on this parameter.

The next two columns address the persistence of TC analytes in soils, water, and air. Data in these two

columns summarize information from the proposed HWIR-Waste database on the estimated half-life of chemicals in air

and the overall degradation rate constants in soils and surface water. Four of the TC analytes are identified as

having long half-lives in air and 12 are persistent (have low degradation rate constants) in soil and/or surface

water. The air half-life values must be interpreted cautiously, as the proposed HWIR-Waste database contains this

information on only about 20 chemicals. Metals and many high-Koc organics would also be expected to have long

half-lives in air if they were bound to particulates. As discussed earlier, the TC analytes with long half-lives

in soil/water systems include primarily the metals and chlorinated pesticides.

The final three columns of Exhibit 3-9 consider the propensity of TC analytes to bioaccumulate in aquatic

and terrestrial ecosystems. The plant-soil bioconcentration factor (BCF) is an estimate of the typical ratio of

the concentration of a constituent in soil to the concentration in a particular kind of plant (in this case, forage

plants consumed by beef and dairy cattle). Similarly, the beef biotransfer factor is an estimated typical ratio of

the concentrations of pollutants in the diet of beef cattle to the resultant concentrations in edible tissue. 

Finally, the BCF and bioaccumulation factor (BAF) values for fish represent the typical ratios of pollutant

concentrations in surface water to that in fish tissue, considering only water exposures or considering all

pathways, respectively. (These value tend to be quite similar for most chemicals.) Although the exhibit

indicates that several constituents may bioaccumulate from soil to forage plants, in reality, only 2,4,5-

trichloropropionic acid (Silvex) has a very high bioconcentration potential. The value of the forage biotransfer

factor for this pesticide is five orders of magnitude greater than for any other chemical (greater than 10 ). 6

Generally the same chemicals have high beef biotransfer factors, fish BCFs, and BAFs, with barium, mercury, and

lindane bioconcentrating only in aquatic systems, and arsenic, chromium, selenium, and silver being significant

for the beef exposure pathways alone.

Summary. These single comparisons indicate the significant potential for many TC analytes to be

transported through multiple media to reach the ultimate receptors. The data in Exhibits 3-8 and 3-9 show that the

chlorinated pesticides (i.e., chlordane, endrin, heptachlor, heptachlor epoxide, hexachlorobenzene,

methoxychlor, pentachlorophenol, and toxaphene), chloroform, and hexachloro-1,3-butadiene have the potential to

participate in indirect exposure pathways and have non-groundwater pathways as their driving pathways. In

addition, several high-toxicity and persistent metals, such as mercury, arsenic, and lead, also are of potential

concern.
Page 3-38

3.5.6 Potential for Acute Adverse Effects of Exposures to TC Analytes

The TC was originally established based on the need to protect individuals from adverse health effects due

to chronic exposures to the TC constituents consumed in groundwater. This approach to protecting against

groundwater exposure risks is conservative because the relatively long time scale involved in groundwater

transport to receptors, under most reasonable assumptions, means that limiting concentrations in any time period

to the low chronic risk-based levels also will protect against short-term adverse effects. Short transient

exposures to high levels of groundwater contaminants are extremely uncommon. Before the concentration of a

pollutant reaches the relatively high level required to cause acute effects, it generally will have exceeded the

allowable chronic exposure level for a long period of time. 

This relationship may not apply to exposure through pathways not involving slow releases to groundwater. 

For example, the rapid evaporation of volatile chemicals from a ruptured container, the catastrophic release due

to overtopping of a surface impoundment, or runoff erosion from an extreme storm event have the potential to result

in short-term acute exposures to humans and environmental receptors. For this reason, EPA has evaluated the

potential level of protectiveness of the TC against acute exposures. EPA evaluated the potential for adverse

effects associated with acute volatilization of chemicals from land management units. The approach was analogous

to the screening-level risk modeling for chronic exposure, except that the short-term releases were calculated and

exposure concentrations were compared to short-term exposure standards. This analysis indicates that the shortterm concentrations of all of the volatile TC analytes calculated at the fenceline were far below applicable

short-term exposure standards (in this case, occupational exposure standards).

This simple modeling does not unconditionally eliminate the possibility of adverse effects from acute

exposures to the TC analytes. Unusual release events, such as fires, or explosions, could result in higher

exposures than calculated assuming simple volatilization. In addition, high winds or other events could result in

high concentrations of particle-bound metals and other non-volatile analytes. The potential for these kinds of

release events strongly depends on specific waste characteristics, site conditions, and management practices.

3.5.7 Potential Risks to Ecological Receptors from TC Analytes

Risks to non-human receptors are the final category of risks evaluated by EPA. Like the inhalation,

surface water, and indirect pathway risks, they were not expressly factored into the derivation of the regulatory

levels for the TC analytes. While a substantial number of the TC chemicals are toxic to ecological receptors, the

protection of ecological receptors was not a specific concern in the rulemaking. This section discusses potential

gaps in the TC characteristic associated with harm to ecological receptors.

Many of the same factors that contribute to potential risks for human receptors also contribute to

potential risks for ecological receptors. Generally, harm to environmental receptors requires release of

chemicals from containment and transport to sensitive receptors without extensive degradation or extreme

dilution, just as in the case of human health risks. Thus, the physical properties of chemicals that contribute to

persistence and transport in the environment, as shown in Exhibit 3-9, are indicators of potentially significant

risks for ecological receptors. The fact that most of the persistent chemicals with high bioconcentration

potentials are also pesticides, which are toxic to certain plants, insects, or other animals, adds to the

potential risks.

The degree of protection of ecological receptors afforded by the TC leachate concentrations does not

appear very high for many of the most toxic pesticides. Exhibit 3-10 compares the TC regulatory levels to two basic

measures of potential aquatic toxicity, the acute and chronic Ambient Water Quality Criteria (AWQC) for the
 45 Federal Register 33110, May 19, 1980. 30

 51 Federal Register 21648, June 13, 1986. 31

Page 3-39

protection of aquatic life. It shows that, for many analytes, the allowable leachate concentrations are many

orders of magnitude above the corresponding AWQC.

The shaded boxes in the table identify TC analytes with regulatory levels greater than 1,000 times the

AWQC. The chemicals falling into this category again include the chlorinated pesticides, chlorobenzene, lead,

mercury, silver, and 2,4,5-trichlorophenol. This ratio indicates that if the TC analytes were released from

wastes to groundwater and from there discharged to surface water, a dilution of at least 1,000-fold would be

required to reduce the concentration to levels not harmful to aquatic biota. Such a scenario may be unlikely,

however, because, as noted above, these chemicals tend to bind strongly to soil and do not move readily in

groundwater. (As is discussed in more detail in Chapter 2, however, some of these chemicals were found in

groundwater at concentrations above health-based levels in the descriptions of environmental releases from nonhazardous industrial waste management units.)

In a more likely scenario, the high ecotoxicity of these chemicals means that runoff transport of

particulate wastes at concentrations not considered hazardous under the TC could cause adverse effects in water

bodies near management units. As noted above, the concern for runoff exposures is borne out to some extent by the

proposed HWIR-Waste modeling, where proposed exit levels are driven by this pathway for disposal in waste piles

and land application units. In the case of silver and endrin (two of the chemicals in shaded boxes in Exhibit 3-

10), the proposed exit levels were driven by runoff releases to surface water. 

Summary. Based on these findings, it appears that the level of protectiveness of the TC is not very high

for some non-human receptors. At a minimum, the ecotoxicity parameters suggest a potential concern associated

with the aquatic toxicity of chlorinated pesticides, as well as a few other chemicals. The severity of these

potential gaps is addressed in more detail in later chapters.

3.6 Potential Gaps Associated with TCLP

This section reviews the technical basis for the Toxicity Characteristic Leaching Procedure (TCLP) and

discusses potential problems associated with its use based on a brief review of available literature and data. 

Specifically, this section focuses on whether the TCLP fails to accurately predict releases from identified

classes of wastes into groundwater and non-groundwater pathways.

3.6.1 TCLP Background

In 1980, prior to development of the TCLP, the Agency adopted the Extraction Procedure (EP) to identify

wastes likely to leach hazardous concentrations of particular toxic constituents into the groundwater under

conditions of improper management. In 1986, the Agency proposed a modified leaching procedure, the TCLP, to 30

replace the EP. The Agency promulgated the final rule on the 31
Page 3-40

Exhibit 3-10

Ratios of TC Leachate Regulatory Levels to

Ambient Water Quality Criteria for Aquatic Lifea

Chemical Acute Chronic (mg/l) (ug/l) to AWQC

Freshwater AWQC

Concentration (ug/l) TC TC Leachate Ratio of TC 

Regulatory Level Concentration Regulatory Level

Arsenic 850 190 5 5000 26

Barium -- -- 100 100000 NA

Benzene 5300 -- 0.5 500 0.09b

Cadmium 3.9 1.1 1 1000 909

Carbon tetrachloride 35200 -- 0.5 500 0.01

Chlordane 2.4 0.0043 0.03 30 6.98E+04

Chlorobenzene 250 50 100 100000 2.00E+04

1,4 Dichlorobenzene 250 50 7.5 7500 150

Chloroform 28900 1240 6 6000 4.8

Chromium 1700 210 5 5000 24

Chromium VI 16 11 --- 5000 455

o-Cresol -- -- 200 200000 NA

m-Cresol -- -- 200 200000 NA

p-Cresol -- -- 200 200000 NA

Cresol -- -- 200 200000 NA

2,4-D -- -- 10 10000 NA

1,2-Dichloroethane 118000 20000 0.5 500 0.025

1,1 Dichloroethylene -- -- 0.7 700 NA

2,4-Dinitrotoluene 330 230 0.13 130 0.57

Endrin 0.18 0.0023 0.02 20 8.70E+04

Heptachlor 0.52 0.0038 0.008 8 2.11E+04

Heptachlor epoxide 0.52 0.0038 0.008 8 2.11E+04

Hexachlorobenzene 6 3.68 0.13 130 35
Page 3-41

Exhibit 3-10 (continued)

Ratios of TC Leachate Regulatory Levels to

Ambient Water Quality Criteria for Aquatic Life

Chemical Acute Chronic (mg/l) (ug/l) to AWQC

Freshwater AWQC

Concentration (ug/l) TC TC Leachate Ratio of TC 

Regulatory Level Concentration Regulatory Level

Hexachloro-1,3-butadiene 90 9.3 0.5 500 54

Hexachloroethane 980 540 3 3000 5.6

Lead 82 3.2 5 5000 1.56E+04

Lindane 2 0.08 0.4 400 5.00E+04

Mercury 2.4 0.012 0.2 200 1.67E+05

Methoxychlor -- 0.03 10 10000 3.33E+06

Methyl ethyl ketone -- -- 200 200000 NA

Nitrobenzene 27000 -- 2 2000 0.07a

Pentachlorophenol 20 13 100 100000 7.69E+04

Pyridine -- -- 5 5000 NA

Selenium 20 5 1 1000 200

Silver 4.1 0.12 5 5000 4.17E+05

2,4,5-TP (Silvex) -- -- 1 1000 NA

Tetrachloroethylene 5280 840 0.7 700 0.83

Toxaphene 0.73 0.0002 0.5 500 2.50E+07

Trichloroethylene 45000 21900 0.5 500 0.02

2,4,5-Trichlorophenol 100 63 400 400000 6.35E+04

2,4,6-Trichlorophenol -- 970 2 2000 2.1

Vinyl chloride -- -- 0.2 200 NA

Notes:

Shaded rows indicate that the ratio of the TC regulatory level to the AWQC for the analyte exceeds 1,000. a

Indicates ratio is to acute AWQC. b
 55 Federal Register 11827, March 29, 1990. 32

 Note that the majority of these data were collected from on-site groundwater monitoring wells and not from drinking water 33

wells, and therefore actual risks likely are lower than would be indicated by these data.

 Lester Sotsky, Arnold & Porter, “Reynolds Metal Company’s Gum Springs Facility,” Memorandum to Steven Silverman, U.S. EPA,

34

September 26, 1996.

Page 3-42

application of the TCLP in 1990. In finalizing the TCLP, the Agency intended to improve the leachate test 32

procedure and eliminate some of the analytical difficulties involved in the EP.

The TCLP is used to quantify the extractability of certain hazardous constituents from solid waste under a

defined set of laboratory conditions. This test is used to evaluate the leaching of TC metals, volatile and

semivolatile organic compounds, and pesticides from wastes. In principle, this procedure simulates the leaching

of constituents into groundwater under conditions found in a municipal solid waste (MSW) landfill. The TCLP,

however, does not simulate the release of contaminants to non-groundwater pathways. The TCLP is most commonly

used by EPA and state agencies to evaluate the leaching potential of wastes, and for determining toxicity. The

TCLP is promulgated in Appendix II of 40 CFR Part 261.24(a) and has been designated as EPA Method 1311 in "Test

Methods for Evaluating Solid Waste, Physical/Chemical Methods - SW-846."

In the TCLP, liquid wastes (those containing less than 0.5 percent dry solid material) are "extracted" by

filtering the wastes through a 0.6 to 0.8 μ glass fiber filter. Non-liquid samples (those containing greater than

or equal to 0.5 percent dry solid material) are:

Reduced to a particle size of less than 9.5 mm (liquid, if any, is separated from the

solid phase) and extracted with an acetate buffer solution with either a pH of 5 or an

acetic acid solution with a pH of 3, depending on the alkalinity of the waste (wastes

with a pH of 5 and above are extracted with the acetic acid solution);

A liquid-to-solid ratio of 20:1 is used for an extraction period of 18 hours; and

The leachate is filtered and combined with the liquid portion of the wastes, if

necessary.

Contaminant analyses then are conducted on the extracts of the liquids and non-liquids.

3.6.2 Limitations of the TCLP

The Agency reviewed TC constituent and concentration data collected on releases from the non-hazardous

industrial waste management units discussed in Chapter 2 (see Exhibit 2-5). These data show that, of the 15 TC

constituents detected in at least three case studies, eight are present in groundwater at levels much higher than

their TC levels. If the wastes passed the TCLP before being placed in the management units, this could indicate 33

that the TCLP underestimated the long-term releases for certain classes of wastes. One of the major limitations of

these data, however, is that they may not reflect current waste analysis or management practices. For example,

some data represent releases from waste disposal that occurred prior to implementation of the TCLP, and thus some

of the releases that exceed TC levels could be due to problems with other extraction procedures or to the lack of

any testing procedure. Nevertheless, some site data (not reported in Chapter 2) exists that may represent

problems with the TCLP. For example, the kiln residues from the treatment of spent aluminum potliners at one

facility are disposed in a monofill as non-hazardous wastes. EPA approved a delisting petition for the kiln 34
 Note, however, that this list of issues is not meant to be comprehensive. Other issues, such as the potential overestimation 35

of the dilution simulated by the TCLP, may need further study.

 van der Sloot, H.A., G.J. de Groot, and J. Wijkstra, "Leaching Characteristics of Construction Materials and Stabilization 36

Products Containing Waste Materials," in P.L. Cote and T.M. Gilliam, eds., Environmental Aspects of Stabilization and

Solidification of Hazardous and Radioactive Wastes, ASTM STP 1033, American Society for Testing and Materials, Philadelphia,

Pennsylvania, 1989; and Willis, et al., "When the TCLP Is Not Enough: Leaching Tests for Solidification/Stabilization

Technologies," Hazardous Materials Controls/Superfund 1991, Proceedings of the 12th National Conference, Hazardous Materials

Control Research Institute, pp. 385-388, December 3-5, 1991.

Page 3-43

residue waste based on TCLP data that showed the target constituents in the TCLP extract to be below treatment

standards (which, for the TC constituents, are lower than the TC regulatory levels). When the leachate from the

monofill was analyzed, however, levels of arsenic were found to be higher than its TC level. Other hazardous

constituents, including cyanide and fluoride, were also found at levels higher than those predicted by the TCLP.

Several technical and practical issues have been raised by the regulated community and others regarding

the applicability of the TCLP for identifying hazardous waste. A number of comments were submitted to the Agency

in response to the June 13, 1986 proposal to replace the EP with the TCLP. The Agency responded to the comments in

the final rule, but also decided to continue to address commenters concerns and further evaluate modifications to

the TCLP. The Agency stated that further improvements in the TCLP will be proposed as they are developed. 

Subsequent to that rulemaking, additional concerns have been raised by commenters during later rulemakings (e.g.,

rules addressing newly listed or identified wastes).

Some of the key issues regarding the TCLP identified from these comments on various rulemakings and from

other sources are outlined below.35

TCLP underestimates leachate from some high alkaline wastes or environments. The high alkalinity of some

wastes may make the TCLP an inappropriate predictor of leachate composition. For example, the addition of acid

during the TCLP might not reduce the pH of high alkaline waste to the same level as would occur over time in the

environment. Thus, long-term leachate concentrations of constituents that are insoluble at higher pH ranges may

be underestimated in the TCLP leachate compared to the actual leachate from the industrial landfills where a longterm acid environment (e.g., from acidic rain water) is present.

Some toxic metal constituents are more mobile at both the higher and the lower pH ranges. For example,

studies show that leaching of metals such as cadmium, chromium, and lead typically is limited when the pH is in the

range of about 8 or 9, but can increase significantly when the pH either increases or decreases. Thus, if a waste 36

is highly alkaline (e.g., pH >11) and the TCLP acidic leaching medium lowers the pH to only about 8 or 9, then the

concentrations of these metals in the TCLP leachate could be significantly lower than would occur from either a

highly alkaline or a highly acidic environment (depending on a number of factors, such as characteristics of any

co-disposed wastes, type of treatment, and characteristics of the soil and rain water).
 "Preliminary Proposal to Require the TCLP in Lieu of the Waste Extraction Test," Memorandum to James Carlisle, Department 37

of Toxics Substances Control, California EPA, from Jon Marshack, California Regional Water Quality Control Board, December 18,

1995; and U.S. Environmental Protection Agency, Technical Background Document and Response to Comments - Identification and

Listing of Hazardous Waste - Method 1311 - TCLP, F-90-TCF-S0004, April 1989.

 Ibid.

38

 61 Federal Register 2338, January 25, 1996. 39

 U.S. Environmental Protection Agency, "Performance Testing of Method 1312 QA Support for RCRA Testing," p. III, June 1989. 40

Page 3-44

Multiple Extraction Procedure (MEP)

The MEP involves an initial extraction with

acetic acid and at least eight subsequent

extractions with a synthetic acid rain

solution (sulfuric/nitric acid adjusted to pH

3). The MEP is intended to simulate 1,000

years of freeze and thaw cycles and prolonged

exposure to a leaching medium. One advantage

of the MEP over the TCLP is that the MEP

gradually removes excess alkalinity in the

waste. Thus, the leaching behavior of metal

contaminants can be evaluated as a function of

decreasing pH, where the solubility of most

metals increases. Currently, the MEP is used

in the Agency's de-listing program.

Several commenters to the June 13, 1986 TCLP

proposal expressed concern regarding the application of

the TCLP to alkaline wastes. They noted that no high

alkaline wastes were included in the development of the

TCLP and, therefore, no conclusions could be made

concerning the actual behavior of these wastes. The MEP,

described in the text box, is one test that the Agency and

others use that may better simulate the long-term leaching

behavior of such wastes.

TCLP underestimates the leachate concentrations

from oily wastes and some paint wastes. Several reports

indicate that oily and some paint wastes tend to clog the

filters used to separate the extract from the solids prior

to analysis, resulting in under-reporting of the

extractable constituent concentrations. Several 37

commenters on the June 13, 1986 TCLP proposal noted that,

in the development of the TCLP, the Agency tested only 11

wastes. These commenters argued that increasing the 38

variety of wastes (to include oily wastes, organic chemical wastes, and municipal wastes) and the number of

extractions performed could refine the TCLP and enhance its accuracy.

TCLP may not accurately mimic conditions commonly found in non-hazardous industrial waste disposal. As

discussed in the 1980 final EP rule, several commenters responding to the proposed use of the EP for evaluating the

leaching of hazardous constituents argued that the co-disposal assumption is not applicable to wastes that are

never co-disposed with municipal solid wastes and thus do not leach at the aggressive rates characteristic of codisposal situations. Thus, the commenters stated, the leachate procedure does not simulate the conditions found

in industrial waste monofills. In response, the Agency stated that most wastes, even those that are unlikely to be

disposed in a municipal landfill, are likely to come into contact with some form of acidic leaching medium during

their management histories or could otherwise encounter environments that could cause the wastes to leach

comparable levels of toxic constituents.

This same debate occurred during development of the TCLP, and it continues today. For example, the Lead

Industries Association Inc., commenting on the Phase IV supplemental proposed rule, cited an EPA study that 39 40
 The chelation property of a reagent (such as acetate and citrate) refers to the ability of the reagent to bind with and 41

solubilize metal contaminants. The low chelation ability of acetate buffer might result in fewer metal constituents being

leached into the extract. 

 "Preliminary Proposal to Require the TCLP in Lieu of the Waste Extraction Test," supra footnote 37. 42

Page 3-45

Synthetic Acid Precipitation Leach Test

(SPLP)

The SPLP is similar to the TCLP, but the

initial liquid-solid separation step has been

eliminated and the acetate buffer extraction

fluid has been replaced by a dilute nitric

acid/sulfuric acid mixture. The TCLP

addresses co-management of industrial and

non-industrial wastes in an organic acid

environment, a scenario that does not match

the disposal setting of many treated wastes,

while the SPLP simulates disposal in an acid

rain environment. The SPLP is currently used

by several state agencies to evaluate the

leaching of TC hazardous constituents from

wastes. 

California Waste Extraction Test

(Cal WET)

Cal WET was developed by the State of

California to classify hazardous wastes. This

test uses sodium citrate buffer as the

leachate, a 10:1 liquid-to-solids ratio, and a

testing period of 48 hours. Cal WET applies a

soluble threshold limit concentration (STLC)

as the regulatory standard. STLC standards

for metal concentrations in the leachate are

similar to those for the TCLP. Cal WET also

develops a Total Threshold Limit

Concentration (TTLC), which is equivalent to

the Total Waste Analysis (TWA) procedure. Cal

WET is a more aggressive test when compared to

the TCLP. That is, Cal WET almost always

extracts higher levels of contaminants, and

the citrate buffer used in this test has

greater chelation effect than the acetate

buffer used in the TCLP.

stated that acetic acid leaching fluid could selectively

solubilize toxicants (specifically lead) and incorrectly

classify the material as hazardous when, in fact, no

mobilization (leaching) would be expected to occur in the

landfill environment. Kennecott Corporation and National

Mining Association, also in response to the Phase IV

supplemental proposed rule, stated similar concerns. The

SPLP (see text box at right) is one test that has been

considered for addressing this issue.

TCLP may underestimate the chelation-facilitated

mobility of some waste constituents. A recent analysis of

the TCLP and Cal WET (see text box at right) indicates that

the low chelation activity of the acetate buffer used in 41

the TCLP may underestimate the ability of leachate

containing chelating agents to mobilize waste

constituents. Cal WET uses a citrate buffer that 42

approximates the chelation ability of many other compounds

of landfill leachate and, thus, overcomes the constraints

of the TCLP test.

TCLP does not account for the oxidation/reduction

reactions occurring in landfills. A recent study noted

that the addition of iron filings to stabilize foundry sand
 Stabilized waste is a concern for the Scoping Study because some non-hazardous industrial waste either is treated (e.g., 43

using stabilization) to reduce the release of hazardous constituents or is derived from characteristically hazardous waste that

has been "decharacterized" via treatment.

 Douglas Kendall, "Impermanence of Iron Treatment of Lead-Contaminated Foundry Sand--NIBCO, Inc. Nacogdoches, Texas," 44

National Enforcement Investigations Center--Project PA9, April 18, 1996.

 Northwestern University, "Chapter 4 - Evaluation of Procedures for Analysis and Disposal of Lead-Based Paint-Removal 45

Debris," Issues Impacting Bridge Painting: An Overview, Infrastructure Technology Institute, FHWA/RD/94/098, August 1995.

 Dusing, D.C., Bishop, P.L., and Keener, T.C., "Effect of Redox Potential on Leaching from Stabilized/Solidified Waste 46

Materials," Journal of Air and Waste Management Association, Vol. 42, N1, p. 56(7), January 1992.

 See footnote 36. 47

 U.S. Environmental Protection Agency, Office of Research and Development, Technical Resource Document - 48

Solidification/Stabilization and Its Application to Waste Materials, June 1993.

 Perry, K.J, Prange, N.E., and Garvey, W.F., "Long-Term Leaching Performance for Commercially Stabilized Waste," 49

Stabilization and Solidification of Hazardous, Radioactive, and Mixed Wastes, Vol. 2, ASTM STP 1123, T.M. Gilliam and C.C.

Wiles, Eds, American Society for Testing and Materials, Philadelphia, pp. 242-251, 1992.

Page 3-46

wastes seems to mask the potential leachability of lead by interfering with the TCLP. If metallic iron (iron 43 44

filings) are added to the waste, the lead concentration in the TCLP extract may be decreased by an oxidation/

reduction reaction to levels below the lead TC level. If, however, the waste is placed in a landfill or surface

impoundment, the iron oxidizes over time and loses its ability to further reduce the lead ions. This results in the

leaching of lead to the environment.

Another recent study reviewed the practice of using iron as an additive in stabilizing paint waste. The 45

study notes that the iron reduces the lead ions in paint waste to the less soluble metallic lead, which is

subsequently removed by filtration from the leachate being analyzed. This use of iron allows the lead-containing

waste to pass the TCLP. The study notes, however, that repeated leaching of the same waste sample increases the

leaching rate to a point where lead is sufficiently solubilized to exceed the TC regulatory level.

Finally, another study showed that oxidation/reduction potential has a significant effect on leaching of

metals from stabilized waste materials. This study showed that the leaching of chromium increases significantly 46

under highly oxidizing conditions, and the leaching of arsenic, vanadium, lead, and iron increase significantly

under reducing conditions.

TCLP may not predict long-term mobility of organic contaminants in some treated wastes. A fairly recent 47

Superfund Innovative Technology Evaluation (SITE) field evaluation examined the long-term performance of

stabilization treatment of lead and other metals, oil and grease, and mixed volatile and semivolatile organic

compounds. Portland cement and a proprietary additive were used as stabilizing agents. Durability was tested 48

with weathering tests by wet-dry and freeze-thaw cycling and by sampling stabilized treated waste after 9 and 18

months of burial. The results showed that organic contaminants were not effectively immobilized (although the

testing also showed that lead and other metals remained highly immobilized, the physical properties of the

stabilized treated waste deteriorated only slightly, and the porosity decreased).

Another study conducted on the long-term leaching performance of commercially stabilized waste

demonstrated a highly waste-dependent effect of time on the TCLP results. In this study, TCLP extraction was 49
 Alternate Soil Leaching Procedures, Interoffice Memorandum to the Environmental Response Division Staff from Alan J. 50

Howard, Environmental Response Division, Michigan Department of Natural Resources, January 5, 1995.

 The TCLP does account for the loss of volatile contaminants that occur during the liquid/solid separation and extraction 51

process; however, this is only for correcting the leachate concentration, not for simulating releases to air.

Page 3-47

performed on both the raw waste and the treated waste. The treated waste consisted of samples at 28, 90, 200, 470,

and 650 days after treatment. The results showed that leachate values for some metallic wastes increased over

time.

TCLP may not be appropriate for some contaminated soil. The Michigan Department of Natural Resources

(MDNR) believes that the TCLP is not appropriate for soils contaminated with cyanides, sulfides, and hexavalent

chromium. Furthermore, MDNR reports that the SPLP (see previous text box) more accurately simulates the 50

conditions of contaminated soil and therefore is an appropriate alternative test for soil contaminated with

cyanides, sulfides, and hexavalent chromium.

TCLP does not predict releases to non-groundwater pathways. As discussed in Section 3.4, the TCLP was

designed to simulate the leaching of waste constituents to groundwater and not for releases to non-groundwater

pathways. The TCLP does not simulate the release of volatile organic contaminants into air either directly or

through entrained dust, nor does it simulate releases through surface runoff.51
Page 3-48

CHAPTER 3. POTENTIAL GAPS ASSOCIATED WITH

HAZARDOUS WASTE CHARACTERISTICS DEFINITIONS .............. 3-1

3.1 Types of Risks Addressed by RCRA Hazardous Waste Characteristics ............. 3-1

3.1.1 Statutory and Regulatory Framework .................................. 3-1

3.1.2 Risks Associated with Physical Hazards ............................... 3-3

3.1.3 Acute Toxic Hazards to Humans ..................................... 3-4

3.1.4 Chronic Toxicity Risks to Humans ................................... 3-4

3.1.5 Risks to Non-Human Receptors ...................................... 3-5

3.1.6 Other Risks Associated with Non-Hazardous Industrial Waste Management . . 3-6

3.2 Ignitability Characteristic .................................................. 3-8

3.2.1 Definition of Ignitability ............................................ 3-8

3.2.2 Potential Gaps Related to Definition of Ignitability ....................... 3-9

3.2.3 Potential Gaps Related to Ignitability Test Methods ....................... 3-12

3.3 Corrosivity ............................................................ 3-12

3.3.1 Definition of Corrosivity .......................................... 3-12

3.3.2 Potential Gaps Related to Definition of Corrosivity ..................... 3-13

3.3.3 Potential Gaps Related to Corrosivity Test Methods ..................... 3-16

3.4 Reactivity ............................................................. 3-16

3.4.1 Definition of Reactivity ........................................... 3-16

3.4.2 Potential Gaps Related to Definition of Reactivity ...................... 3-17

3.4.3 Potential Gaps Related to Reactivity Test Methods ...................... 3-19

3.5 Potential Gaps Associated with the Toxicity Characteristic ...................... 3-19

3.5.1 Definition of Toxicity Characteristic ................................. 3-19

3.5.2 Changes in Groundwater Pathway Analysis ........................... 3-21

3.5.3 Potential Inhalation Pathway Risks Associated with TC Analytes .......... 3-27

3.5.4 Potential Risks from Surface Water Exposures ......................... 3-33

3.5.5 Potential Indirect Pathway Risks from TC Analytes ..................... 3-35

3.5.6 Potential for Acute Adverse Effects of Exposures to TC Analytes .......... 3-38

3.5.7 Potential Risks to Ecological Receptors from TC Analytes ............... 3-38

3.6 Potential Gaps Associated with TCLP ....................................... 3-39

3.6.1 TCLP Background ............................................... 3-39

3.6.2 Limitations of the TCLP ........................................... 3-42
Page 3-49

Exhibit 3-1. Risks Potentially Associated with Non-Hazardous Industrial Waste Management ........ 3-7

Exhibit 3-2

Materials Formerly Classified by DOT as Combustible Liquids

(which generally are not RCRA ignitable) ...................... 3-11

Exhibit 3-3

Other Definitions of Reactivity .......................... 3-18

Exhibit 3-4

TC Constituents and Regulatory Levels (mg/l) ................... 3-20

Exhibit 3-5

Comparison of TC Regulatory Concentrations

and HWIR-Waste Proposed Exit/Leach Levels .................... 3-25

Exhibit 3-6

Summary of Inhalation Pathway Screening Methods,

Input Data, and Models Used for Bounding Risk Analysis ............... 3-29

Exhibit 3-7

Emission Fraction for Air Releases of Volatile TC Analytes ............... 3-30

Exhibit 3-9

Major Fate and Transport Parameters for TC Analytes ................. 3-36

Exhibit 3-10

Ratios of TC Leachate Regulatory Levels to

Ambient Water Quality Criteria for Aquatic Life ................. 3-40
Page 4-1

CHAPTER 4. POTENTIAL GAPS ASSOCIATED WITH

NON-TC CHEMICALS

This chapter identifies potential gaps in the hazardous waste characteristics associated with chemicals

not on the toxicity characteristic list. Chemicals and chemical classes are identified as potential gaps based on

their hazardous properties such as toxicity to humans and ecological receptors, their fate and transport

properties such as persistence and bioconcentration potential, and their potential for occurrence in nonhazardous industrial wastes. This approach to identifying gaps is complemented by the approach discussed in

Chapter 5, which identifies gaps in terms of the important environmental risks and their potential association

with waste management, rather than focusing on specific chemicals.

4.1 Overview of Methodology

EPA identified potential gaps in the characteristics associated with non-TC chemicals through a six-step

process, as shown in Exhibit 4-1. Each of these steps is described below.

Step 1: Identify and Classify Known Non-Hazardous Industrial Waste Constituents

An essential task in this analysis is identifying a universe of chemicals that are either known or likely

to be present in non-hazardous industrial wastes, excluding TC analytes (which are addressed in Chapter 3). In the

analysis that follows, these two classes of chemicals are referred to as known non-hazardous industrial waste

constituents and possible non-hazardous industrial waste constituents, respectively. As described in Section

4.2, the identification of the "known" non-hazardous constituents is relatively straightforward, although

reliable data on the composition of non-hazardous industrial waste are limited. The data sources used to identify

these constituents are shown in the top panels of Exhibit 4-1. They are the non-hazardous industrial waste release

descriptions (discussed in Chapter 2), the Industrial Studies Data Base (ISDB), Effluent Guidelines Development

Documents, and Listing Documents from recent rulemakings for dyes and pigments and solvent wastes. As discussed

in Section 4.2, the distinguishing characteristic that makes a chemical a “known” non-hazardous industrial waste

constituent is that it has been documented through direct chemical analysis to occur either in non-hazardous

industrial waste or in environmental media contaminated by releases from non-hazardous industrial waste

management units.

Step 2: Identify and Screen Possible Non-Hazardous Industrial Waste Constituents

In addition to the chemicals that are known to be present in non-hazardous industrial wastes, EPA

identified other chemicals that have a high likelihood of being present in such wastes and could pose significant

risks to human health or the environment. Unlike the known non-hazardous industrial waste constituents, however,

the possible waste constituents have not been confirmed as non-hazardous industrial waste constituents through

direct chemical analysis in any of the data sources used by the Agency. To identify non-hazardous industrial waste

constituents that could pose risks to human health or ecological receptors, the Agency reviewed 36 lists of

chemicals created for regulatory and advisory purposes by EPA, other federal agencies, states, other countries,

and advisory and scientific bodies. These lists were originally created based on criteria such as toxicity, fate

and transport characteristics, production volume, widespread use, and detection in environmental media.
Page 4-2

Insert Exhibit 4-1 Flow Chart of Procedures Used to Identify Non-TC Chemicals Posing Potential

Gaps in the TC Characteristics

In graphics
Page 4-3

Rather than include all the chemicals on these lists as possible non-hazardous industrial waste

constituents, EPA narrowed the list of chemicals to those most likely to pose significant risks to human health and

the environment. The screening was performed in two steps, as shown in the upper right-hand panels of Exhibit 4-1. 

First, chemicals were screened with regard to individual toxicity and fate and transport properties. Then, the

resulting high-hazard chemicals were screened against 1994 national Toxic Release Inventory (TRI) release data,

serving as a proxy for potential occurrence in waste. Section 4.3 describes the process of compiling and screening

possible non-hazardous industrial waste constituents.

Step 3: Apply Hazard-Based Screening Criteria

In this step, which is described in detail in Section 4.4, EPA compared the lists of known and possible

non-hazardous industrial waste constituents and screened them against single and multiple hazard-based screening

criteria. In Step 2, individual chemicals that are possible non-hazardous industrial waste constituents were

screened on the basis of single indicators of hazard (e.g., a low reference dose or a high bioconcentration

factor). This step refines this analysis by examining both the known and possible non-hazardous industrial waste

constituents against single and multiple indicators of toxicity, fate, transport, and occurrence in waste, and by

reviewing the implications of this screening for classes of chemicals.

Step 4: Review Relevant Multipathway Risk Modeling Results

Section 4.5 reviews the results of the multipathway risk modeling conducted as part of the proposed HWIRWaste (Hazardous Waste Identification Rule for Process Wastes) determination of exit levels, where available for

chemicals on the combined list of known or possible non-hazardous industrial waste constituents. The proposed

exit levels and risk-driving pathways provide information on the relative risks posed by the various constituents

and on the most important exposure pathways.

Step 5: Identify Potential Acute Hazards

In the prior steps, the evaluation of potential hazards associated with the possible and known nonhazardous industrial waste constituents has focused on chronic toxic effects. In Section 4.6, the possible and

known constituents are compared to acutely hazardous chemical lists developed by EPA and other regulatory

agencies. This analysis thus addresses risks from acute exposures and from physical hazards associated with

reactivity, flammability, and corrosivity.

Step 6: Summarize Findings

Chapter 4 concludes by identifying non-TC chemicals and groups of chemicals that constitute potential

gaps in the hazardous waste characteristics. Section 4.7 presents a table identifying these potential gaps, the

rationale for their identification, and the major issues and data gaps remaining to be resolved to judge the

severity of these potential gaps.

4.2 Identify and Classify Known Constituents of Non-Hazardous Industrial Wastes

Chemicals present in non-hazardous wastes that have been released from non-hazardous industrial waste

management units into the environment may constitute potential gaps in the hazardous waste characteristics. This

section reviews the available evidence concerning such chemicals. Reliable data concerning the chemical

composition of non-hazardous industrial wastes, however, are quite limited for two major reasons. First, such

wastes may be generated by virtually any industrial facility or operation and are inherently heterogeneous. 

Second, state requirements to analyze non-hazardous industrial wastes and to report analytical results are quite

limited.
Page 4-4

In the course of this Scoping Study, the Agency identified four sources of information regarding the

composition of non-hazardous industrial wastes:

The descriptions of environmental releases from non-hazardous industrial waste

management facilities, compiled as part of this Scoping Study, which were summarized in

Chapter 2;

The Industrial Studies Data Base (ISDB), which includes information on point of generation

constituent concentrations on various industries;

Chemicals identified as being present in liquid non-hazardous wastes by EPA Effluent

Guideline Development Documents, as summarized in the Capacity Analysis for the Phase

III Land Disposal Restrictions (LDR) Rule; and

Chemicals identified as being present in non-hazardous industrial waste that were not

listed as hazardous wastes in background documents for recent Agency listing/no-listing

proposals for pigments and dyes industries and for solvents.

The first source provides information on chemicals detected in environmental media (primarily groundwater) that

were released from non-hazardous industrial waste management facilities, while the other three sources provide

information on the composition of non-hazardous industrial wastes. Although not reflected in this Study, in

future investigations the Agency will consider examining the constituents present in remediation waste from nonhazardous industrial waste management units.

The descriptions of environmental releases in Chapter 2 identify the constituents found in environmental

media near non-hazardous industrial waste management units, their maximum detected concentrations, the types of

units from which the releases occurred, and the industries responsible for the releases. The release descriptions

provide direct evidence of potential environmental exposure to non-hazardous industrial waste constituents and

damage to human health and the environment. They, however, do not encompass all instances where non-hazardous

industrial waste management has resulted in releases to the environment or other potential risks. As noted in

Chapter 2, the release descriptions come from only a small proportion of the states. However, they do represent a

large proportion of the readily identifiable releases from facilities regulated by state non-hazardous industrial

waste programs.

In addition, some types of occurrences (e.g., fires and explosions) and units (e.g., waste piles) are

generally not regulated by these state programs, and would not show up in the records EPA examined. The

quantitative data from these descriptions generally were limited to groundwater monitoring results. Few releases

to other media were identified. In addition, the chemicals identified tend to be those whose monitoring is

required under existing regulatory programs. The potential for identifying chemicals not already recognized as

hazardous is therefore limited. Finally, the data sources evaluated did not provide useful information on various

types of uses constituting disposal, such as cement additives, soil amendments, or aggregate.

The ISDB was the second source of data used to identify known waste constituents. EPA has maintained this

data set since 1982. It contains information on point-of-generation constituent concentrations for 16

industries. The sources of information include RCRA Section 3007 questionnaires, plant visit reports, sampling

and analysis reports, and engineering analysis. Its major limitations include data that are sometimes more than

15 years old and the coverage of only selected industries.
 U.S. Environmental Protection Agency, Office of Solid Waste, Background Document for Capacity Analysis for Land Disposal 1

Restrictions Phase III - Decharacterized Wastewaters, Carbamate Wastes, and Spent Potliners (Final Rule), Volume 1, February

1996.

 U.S. Environmental Protection Agency, Office of Solid Waste, Assessment of Risks from the Management of Used Solvents 2

(Draft), May 3, 1996.

 U.S. Environmental Protection Agency, Office of Solid Waste, Listing Background Document: Final Hazardous Waste Listing 3

Determination for the Dyes and Pigments Industries, November 30, 1994, non-confidential business information version.

Page 4-5

The third data source was information gathered by EPA's Office of Water in preparing Effluent Guidelines

Development Documents. These data are summarized in OSW's Capacity Analysis Background Document for the Phase III

LDR. The data describe the composition of non-hazardous industrial wastewaters generated by major industry 1

groups. These wastewater data are of varying age, and therefore their continued representativeness is unclear. 

Also, the number of analytes in the database is quite limited. As seen below, a very high proportion of the waste

constituents identified in this source also are identified in one or both of the two data sources described above. 

Thus, the effluent guidelines data serve mainly to confirm data from the other sources.

The Agency also reviewed two recent proposed listing decisions for hazardous wastes, those for solvent

wastes and for wastes from the dyes and pigments industries. Several additional chemicals were identified as

being constituents of unlisted (non-hazardous) solvent waste streams that were not found in any of the other data

sources: 2-methoxyethanol, 2-ethoxyethanol acetate, cyclohexanol, isophorone, and diethylamine. No non- 2

hazardous industrial waste constituents from the dyes and pigments industry were identified, because all of the

data concerning the compositions and generation rates of these wastes were held as confidential by the industries

that submitted data.3

 Excluding TC analytes, which are addressed in Chapter 3, a total of 146 chemicals were identified in the

release descriptions, 183 in the ISDB, and 19 in the effluent guidelines data. An additional five unique

constituents were found in the listings background document. Overall, a total of 250 unique chemicals were

identified.

The chemicals and waste constituents identified in the three data sources are sorted into major chemical

classes and shown in Exhibit 4-2. These constituents span a wide range of chemical classes. Even with a number of

possibly redundant entries, the most common category of chemicals was metals and inorganics, with 48 chemicals. 

Other prominent families of chemicals included volatile chlorinated organics (38), other semivolatile organics

(46), other volatile organics (45), and pesticides and related compounds (29). Included among the chlorinated

organics are several trihalomethanes and two chlorofluorocarbons. The “other semivolatile” category contains a

wide range of compounds, many of which are found only in the ISDB data. The pesticides category contains mostly

chlorinated organic pesticides and intermediates, but also contains some nonchlorinated compounds.
Page 4-6

Exhibit 4-2. Known Non-Hazardous Industrial Waste Constituents Found in Case Studies, ISDB, Listings Documents,

and Effluent Guidelines by Chemical Class
Page 4-7

Less prominent categories of chemicals include the PAHs (18 compounds), volatile hydrocarbons (12),

phenolic compounds (8), and phthalate esters (6). The PAHs range from low-molecular weight, noncarcinogenic

compounds (such as naphthalene) to the higher molecular weight carcinogens and mutagens (such as benzo(a)pyrene). 

All but one of the volatile hydrocarbons (styrene) are commonly found as constituents in kerosene, gasoline, and

related fuels. Styrene is a monomer used in plastics production. The phenolic compounds include creosote

components (cresols) and two nitrophenols. Most of the phthalate esters are found in all the first three data

sources, including the suspect carcinogen bis-(2-ethylhexyl)-phthalate. Polychlorinated biphenyls (PCBs) and

chlorinated dioxins (represented by 2,3,7,8-TCDD) were found in the ISDB.

The number of compounds in the various categories does not necessarily reflect the relative potential

importance of the chemicals or categories. As noted above, some chemicals occur only in one database, while others

occur in two, three, or all four. In addition, some chemicals occur in more than one release description, that is,

at more than one facility, or are identified as waste constituents from more than one industry group. Except for

the chemicals in the release descriptions, there is no indication of the relative concentrations of the chemicals

in wastes.

Given the wide range of chemical classes represented in the lists, and the relatively small total number

of non-TC chemicals in the four datasets (250), the Agency found no convincing reason to eliminate any candidate

chemicals from inclusion in the gaps analysis. Given that toxicological and fate and transport data are available

for most of these chemicals, all the chemicals were carried forward for further analysis.

4.3 Identify Possible Non-Hazardous Industrial Waste Constituents of Potential Concern

This section describes the approach to identifying additional chemicals that might constitute potential

gaps in the hazardous waste characteristics. Unlike the previous analysis, which began with four relatively

narrow and specific data sources, this analysis begins with a wide range of data sources, in order to avoid

excluding chemicals of potential concern. Subsequently, a substantial proportion of the large universe of

chemicals are screened out on the basis of toxicity, fate and transport characteristics, and potential for

occurrence in waste. A large portion also could not be evaluated because of a lack of data. The result is a focused

list of possible non-hazardous industrial waste constituents that could pose significant risks to human health or

the environment. The list of possible non-hazardous industrial waste constituents supplements the list of known

non-hazardous industrial waste constituents developed in the previous section.

4.3.1 Approach to Identifying Potentially Hazardous Chemicals

Excluding TC analytes, EPA identified over 2,300 distinct chemicals from 36 regulatory and advisory lists

originally created by EPA, other federal agencies, state and national regulatory agencies, and special

environmental task forces and advisory bodies. Exhibit 4-3 identifies these lists. The RCRA regulatory lists

included are the 40 CFR 261 Appendix VII and VIII lists of hazardous waste constituents, the proposed HWIR-Waste

Chemicals, and the HWIR-Media “Bright Line” chemicals. Other major federal regulatory lists include the Clean

Water Act Section 307 Toxic Pollutants and Section 311(b)(2) Hazardous Substances, the CERCLA list of hazardous

substances with reportable quantities, the Emergency Planning and Community Right-to-Know (EPCRA) Toxic Chemicals

and Extremely Hazardous Substances lists, the Clean Air Act Amendments Section 112(b) Hazardous Air Pollutants and

Section 112(r) Regulated Toxic Substances, and chemicals for which OSHA has published Permissible Exposure Limits

(PELs). The U.S. Department of Transportation (DOT)
Page 4-8

Exhibit 4-3. Lists Used to Identify Possible Non-Hazardous Industrial Waste Constituents

RCRA Section 3001 Hazardous Waste, 40 CFR Part 261, Appendix VII

RCRA Section 3001 Hazardous Waste, 40 CFR Part 261, Appendix VIII

CWA Section 307 Toxic Pollutants

CWA Section 311(b)(2)(A) List of Hazardous Substances

CERCLA Hazardous Substances Reportable Quantity List

CAA Section 112(b) Hazardous Air Pollutants

CAA Section 112(r) Regulated Toxic Substances

HWIR-Media (Bright-Line) Chemicals

HWIR-Waste Chemicals

HWIR-Waste Ecotoxicity Chemicals

OSHA Permissible Exposure Limits for Chemicals

EPCRA Section 302 Extremely Hazardous Substances

EPCRA Section 313 Toxic Chemicals List

Industrial Studies Data Base

Canada's Toxic Substances Management Policy

Canadian ARET Toxics Scoring Protocol (A1-A2 LISTS)

Canadian ARET Toxics Scoring Protocol (B1 LIST)

Canadian ARET Toxics Scoring Protocol (B2 LIST)

Canadian ARET Toxics Scoring Protocol (B3 LIST)

Chemicals on Five or More Lists for Short-Term Exposure

Criteria to Identify Chemicals for Sunsetting in Great Lakes Basin

Deferred Toxicity Characteristic Chemicals

Effluent Guidelines Chemicals

Potential Endocrine Disruptors

EPA Hazardous Substance Task Force (Levels 1 and 2)

FIFRA Active Ingredients

Focus Chemicals for the Great Waters Study (USEPA 1991)

Great Lakes Water Quality Agreement Standard Methods Chemicals

Highly Flammable Chemicals (Based on Several Lists)

Highly Reactive Chemicals (Based on Several Lists)

Michigan Critical Materials Register

Persistent Bioaccumulative Chemicals Screening

Proposed Water Quality Guidance, Great Lake Systems (1994)

UN ECE Task Force on Persistent Organic Pollutants (1993)

University of Tennessee Chemical Ranking System (1994)

DOT Hazardous Materials Transportation Act, Hazardous Materials Regulationsa

Notes:

ched manually. Data base sear a
 U.S. Environmental Protection Agency, Office of Solid Waste and Emergency Response, Report of the EPA Hazardous Substances 4

Task Force, April 1992.

 U.S. Environmental Protection Agency, Office of Air Quality, Planning and Standards, Deposition of Air Pollutants to the 5

Great Waters, First Report to Congress, Publication EPA-453/R-93-055, May 1994.

 U.S. Environmental Protection Agency, Office of Solid Waste, November 15, 1996. 6

Page 4-9

Hazardous Materials Transportation Act (HMTA) Hazardous Materials Registry (HMR) also was used to identify

potential gap chemicals, but could not be directly included in the database in time because of format differences

in the available machine-readable forms of the list.

Some of the advisory lists that were included are the 1992 EPA Hazardous Substance Task Force's Level 1 4

and Level 2 hazardous chemicals that were identified as not being controlled under RCRA or DOT regulations, the

Focus Chemicals for the Great Waters Study, chemicals identified by Environment Canada under the ARET Toxics 5

Scoring Protocols, chemicals identified by the University of Tennessee Chemical Ranking System, and the Michigan

Critical Materials Register. Some lists address specific types of hazards, such as potential endocrine

disruptors, acutely toxic chemicals, highly flammable chemicals, and highly reactive chemicals. Brief

descriptions of the lists and the selection criteria that were applied to derive them are provided in "Background

Document: Identification of Chemicals from Regulatory and Advisory Lists Representing Potential Gaps in the

Hazardous Waste Characteristics."6

Naturally, there is a high degree of overlap among the chemical lists. Some lists are subsets of,

combinations of, or otherwise derived from other lists. Nonetheless, the chemicals identified represent a very

broad spectrum of potential hazards. High-volume and highly toxic chemicals appear on many lists, as do acutely

toxic, flammable, and reactive chemicals. Several lists specifically seek to include carcinogens, mutagens, and

teratogens. Some lists are derived based on considerations of ecotoxicity, persistence, and bioaccumulation

potential, or based on specific environmental media or geographical concerns. The overall goal in the Scoping

Study was to identify the broadest possible set of chemicals of potential concern, and then to screen them down to

the chemicals with the highest potential to pose risks to human health or the environment.

4.3.2 Screening Approach

EPA performed the hazard-based screening of potentially hazardous constituents in two steps. First, the

entire list of chemicals was screened against criteria related to toxicity to humans and aquatic organisms and

separately against various fate and transport criteria. Chemicals for which data were not available for at least

one of these criteria were not included in further analysis. In the second step, EPA took all of the chemicals

identified as either highly toxic, mobile, persistent, or bioaccumulative and first screened them against the

proxy for occurrence in waste, namely the TRI release data. Any chemical passing this screen has a high potential

for occurrence in waste and was identified as a possible non-hazardous industrial waste constituent. Chemicals

were also retained in the analysis if they were not on the TRI list. Only the chemicals confirmed as having low

releases through the TRI data were eliminated from being possible constituents.

The criteria considered for use in screening (both the possible constituents described in this section

and the combined lists discussed in Section 4.4) are summarized in Exhibit 4-4. These criteria were derived using

professional judgment to provide a reasonable level of discrimination between
Page 4-10

Exhibit 4-4

Criteria Considered for Screening Non-Hazardous Industrial Waste Constituentsa

Parameter Cutoff Value Rationale

I. Toxicity Values

Oral RfD <1.3x10 mg/kg-day 50th percentile -2

Oral CSF Any Value All Suspect Carcinogens

>2.9x10 (mg/kg-day) 50th percentile -1 -1

Inhalation RfC <1x10 ug/m 50th percentile -2 3

Inhalation UR Any Value All Suspect Carcinogens

>3.3x10 (ug/m ) 50th percentile -4 3 -1

Primary MCL <5x10 mg/l 50th percentile -2

Acute AWQC <130 mg/l 50th percentile

Chronic AWQC <5.2 mg/l 50th percentile

II. Fate and Transport Parameters

Fish BCF >1,000 l/kg About 85th percentile, lists range from 500-100,000

Fish BAF >1,000 l/kg About 50th percentile, lists range from 500-15,000

Kow >100,000 (unitless) About 75th percentile, lists range from 10,000-1,000,000

Beef Biotransfer >7.8x10 day/kg 75th percentile -3

Vegetable Root CF >15 (ug/gm)/(ug/gm) 75th percentile

Forage BCF >3.5 (ug/gm)/(ug/gm) 75th percentile

Henry's Law Constant (kH) >1x10 atm-M /mole 50th percentile, moderately volatile -5 3

Vapor Pressure >1.3x10 atm About 70th percentile = 1 mm Hg -2

Air-Leafy Plant Factor >5.3x10 (ug/gm)/(ug/gm) 75th percentile -4

Air Half Life >0.15 years 75th percentile

Soil Deg. Constant <0.5 year About 75th percentile, DAF risk reduction = 100x -1

Water Deg. Constant <0.5 year About 75th percentile, DAF risk reduction = 100x -1

III. Indicators of Possible Occurrence in Waste

1994 TRI Release Data >10 lbs. Includes 99 percent of all releases to air, water, and land 6

(including underground injection)

1994 Production Data (TSCA >10 lbs. Indicates potential for widespread use, occurrence in

Inventory Update) waste and release potential

6

 All of these criteria were considered for use in the screening of both the possible non-hazardous industrial waste a

constituents and the combined lists discussed in Section 4.4. As discussed in the text, only a subset of these criteria

ultimately were used.
 Background Document: Identification of Chemicals from Regulatory and Advisory Lists Representing Potential Gaps in the 7

Hazardous Waste Characteristics, supra footnote 6.

 U.S. Environmental Protection Agency, Office of Solid Waste, EPACMTP Background Document for Finite Source Methodology for 8

Chemical with Transformation Products, Chapter 6, 1995.

Page 4-11

chemicals with relatively high-hazard potential and those with lower potential. For most toxicity parameters,

which were available only for a relatively small number of more toxic chemicals, the cutoff values were set at the

50th percentile of the entire range of values. For many fate and transport parameters, the criteria were set at or

around the 75th percentile (or 25th percentile, if a low value implied high hazard potential) of the entire range

of the parameter values for all of the chemicals for which the parameter was available. In some cases, the

screening criteria were set at levels generally recognized as indicative of hazard potential.

In the course of the Scoping Study, many different criteria for and approaches to the screening process

were evaluated; the background document to this Study provides further detail. The criteria and approach 7

described in this section is a relatively simple one that evolved from those previous efforts. One of the major

lessons learned in that work was that screening is inherently imprecise, and no single screen will catch or exclude

all the chemicals desired. Another lesson learned is that screening large lists against complex criteria can

quickly become very complicated, and the return on the complexity, in terms of useful information, can be quite

low. Therefore, EPA has focused on a relatively small number of criteria that are important in determining risk

potential and has critically interpreted the results of the screening.

In the case of carcinogens, two sets of criteria were used. The first set indicates whether a cancer slope

factor (CSF) had been promulgated for the chemical. The second indicates whether an inhalation unit risk (UR) had

been developed. These criteria identified the bulk of human carcinogens. For noncarcinogenic effects, two sets

of criteria again were used. The first indicates whether an ingestion reference dose (RfD) had been developed at a

sufficiently toxic level for the purposes of this analysis (i.e., below the 50th percentile). The second

indicates whether an inhalation Reference Concentration (RfC) had been developed below the 50th percentile. For

aquatic effects, the 50th percentile of the Chronic Ambient Water Quality Criteria (AWQC) was used.

EPA used several criteria to screen fate and transport properties. The screening criteria for the fish

bioconcentration factor (BCF) and bioaccumulation factor (BAF) were both set at 1,000 l/kg, the beef biotransfer

factor was set at 7.8x10 day/kg, and the octanol-water partition coefficient (Kow) was set at 10 . These four -3 5

values indicate the potential for the chemicals to be taken up and/or accumulated by organisms. The vapor pressure

criterion, used as a proxy for volatilization release, was set at 1 mm Hg. A Henry's Law constant (kH) value of 10-5

atm-m /mole was also used to identify chemicals with high volatilization potential. The criterion used to 3

identify persistent chemicals in soil or water (degradation rate constant less than 0.5/year) was selected based

on an analysis of the EPACMTP findings for organic pollutant transport in groundwater, which indicated that, at

rate constants above this value, the calculated DAF values begin to differ substantially from those for nondegrading pollutants with similar properties.8

As noted in Section 3.5, the screening-level risk analysis also was used to identify screening criteria

and their importance. For example, Henry’s Law constants were found not to be a good indicator of the potential for

long-term volatilization releases, so that the parameter is not used as a primary screening factor (although it is

examined briefly in the next section). Instead, vapor pressure is used to screen chemicals for volatilization

release. Even this screen must be interpreted cautiously, however, since chemicals with low vapor pressures can

still volatilize from treatment units if no other processes are occurring to limit the releases.
 Toxicological criteria only have a potential to screen out chemicals because, as discussed below, chemicals may be 9

considered high hazard (for the purposes of this analysis) because of fate and transport characteristics.

Page 4-12

The primary data source that is used as a proxy for occurrence of hazardous chemicals in non-hazardous

industrial wastes is the release data, reported under the Emergency Planning and Community Right-to-Know Act

(EPCRA) Toxic Release Inventory (TRI) requirements. For purposes of the screening conducted for this study, EPA

considered those chemicals with releases to air, land, water, and underground injection exceeding one million

pounds in 1994. Under EPCRA Section 313, facilities with more than 10 full-time employees that are classified in

SIC codes 20 through 39 (i.e., manufacturing) must submit reports if they manufacture or process more than 25,000

pounds of a TRI chemical or otherwise use more than 10,000 pounds of a TRI chemical in a given calendar year. There

were a total of 73 unique chemicals and 10 classes of chemicals in this category, out of the 345 individual

chemicals for which reports are required. These chemicals account for greater than 99.8 percent of the total TRI

releases of all chemicals. As discussed in Section 4.4.2, the combined list of known and possible non-hazardous

industrial waste constituents were also screened against non-CBI 1994 production data from the TSCA Inventory.

A major limitation of this screening approach is that quantitative toxicity and fate and transport

parameter values were available for only a fraction of the over 2,300 non-TC chemicals identified. Human toxicity

parameters were available for just over 430 chemicals, ambient water quality data for 105 chemicals, and complete

fate and transport data for 194 chemicals. For this reason, the screening approaches were supplemented by

searching lists that identify chemicals presenting specific types of hazards, even if no quantitative parameter

value was available, and by applying professional judgment to identify where potential risk findings for

individual chemicals may be generalized to broader classes of chemicals. The results of this screening are

described in a background report (see footnote 6).

4.3.3 Toxicity, Fate, and Transport Screening for Possible Non-Hazardous Industrial Waste

Constituents

Exhibit 4-5 summarizes the results of the screening for possible non-hazardous industrial waste chemicals

against the toxicity criteria. The first two columns indicate the chemicals that are suspect or known human

carcinogens having ingestion CSFs or inhalation URs. The last three columns identify the chemicals with oral

RfDs, inhalation RfCs, and AWQCs below the 50th percentile of these parameter values (a low value indicates high

toxicity) for all chemicals for which these values have been developed. Note that this table does not include TC

analytes or chemicals previously identified as known non-hazardous industrial waste constituents.

As noted previously, the number of chemicals identified on all 37 lists of chemicals is much greater than

the numbers of chemicals for which toxicity parameters have been developed. Furthermore, the list of chemicals,

which includes practically all of the known chemicals from Section 4.2 and all of the TC analytes, includes almost

all chemicals for which these toxicity values have been derived. Thus, the toxicological screen has the potential9

to screen out most of the possible non-hazardous industrial waste constituents simply because most of the

constituents do not have toxicity values, and therefore the effectiveness of the individual toxicity screening

criterion is substantially
Page 4-13

Exhibit 4-5. Toxicity Screening Results for Possible Non-Hazardous

Industrial Waste Constituents

Chemicals with CSFs Chemicals with Unit Risks Chemicals with Low RfDs

2,4,6-Trinitrotoluene 1,3-Butadiene

3,3'-Dichlorobenzidine Aramite 1,1,2 Trichloropropane

4,4'-Methylenebis(N,N-dimethyl)benzenamine Asbestos (friable) 1,2,4 Tribromobenzene

Acephate Azobenzene 1,3,5-Trinitrobenzene

Aramite Benzidine 1,3 Phenylenediamine

Azobenzene Bis(chloromethyl) ether 1,4 Dibromobenzene

Benzidine Hexachlorocyclohexane 1,4 Dithiane

Bis(2-ethylhexyl) adipate HxCDD 2-Chlorophenol

Bis(chloromethyl) ether N-Nitrosodi-n-butylamine 2-Cyclohexyl-4,6-dinitrophenol

Cyclotrimethylene trinitramine N-Nitrosodiethylamine 2,3 Dichloropropanol

Dichlorvos N-Nitrosopyrrolidine 2,4,5-T acid

Folpet Nickel subsulfide 2,4,6-Trinitrotoluene

Fomesafen Propylene oxide 2,4-DB

Furmecyclox 2,6-Dimethylphenol

Hexachlorocyclohexane 3,4 Dimethylphenol

Hexachlorodibenzo p dioxin, mixture (HxCDD) Acephate

N-Nitrosodi-n-butylamine Acetataldehyde, trichloroN-Nitrosodi-n-propylamine Acifluoren, sodium salt

N-Nitrosodiethanolamine Alachlor

N-Nitrosodiethylamine Aldicarb sulfone

N-Nitrosomethylethylamine Aluminum phosphate

N-Nitrosopyrrolidine Ametryn

Prochloraz Amitraz

Propylene oxide Avermectin B1

Trifluralin Bentazon

(50th percentile)

Benzidine

Bis(tributyltin) oxide

Captafal

Carbamothioic acid, dipropyl-S-propyl ester

Carbosulfan

Chlorpyrifos

Cyclotrimethylene trinitramine

Cyhalothrin

Decabromodiphenyl oxide

Demeton

Dichlorvos

Dicrotophos

Dinitrobutyl phenol

Diquat

Diuron

Dodine

EPN

Ethion

Ethylene thiourea

Fenamiphos

Flometuron

Fluvalinate

Fonofos

Glufosinate ammonium

Glycidylaldehyde

Haloxyfop methyl
Exhibit 4-5. Toxicity Screening Results for Possible Non-Hazardous

Industrial Waste Constituents (continued)

Page 4-14

Low RfDs (continued) Low RfCs Low AWQCs

(<50th percentile) (50th Percentile) (50th percentile)

Hexabromobenzene 2-Chloroacetophenone Azinphos-methyl

Hexachlorophene Antimony trioxide Chlorpyrifos

Hydramethylnon Arsine Demeton

Imazalil Chlorine dioxide Malathion

Lactofen Dichlorvos Mirex

Linuron Hexamethylene-1,6-diisocyanate

Maneb Methylenebis(phenylisocyanate)

Mecoprop Toluenediisocyanate (mixed isomers)

Mercuric chloride Triethylamine

Merphos Vinyl bromide

Methacrylonitrile

Methamidophos

Methidathion

Methoxone

Methyl mercury

Mirex

N,N-Dimethylaniline

Naled

NuStar

Octabromodiphenyl ether

Oxydiazon

Oxyfluorfen

Parquat dichloride

Pentabromodiphenyl ether

Phenylmercuric acetate

Primiphos methyl

Prochloraz

Prometryn

Propachlor

Propanil

Propargyl alcohol

Propiconazole

Propoxur

Quinalphos

Quintozene

Quizalofop-ethyl

Rotenone, commercial

S,S,S-Tributyltrithiophosphate

Selenious acid

Simazine

Sodium azide

Sodium fluoroacetate

Strychnine

Terbacil

Terbutryn

Tetraethyl lead

Thallium chloride TlCl

Thallium(I) acetate

Thallium(I) carbonate

Thallium(I) nitrate

Thallium(I) sulfate

Thiobencarb

Triallate

Tribenuron methyl

Trifluralin

Warfarin

Zinc phosphide
Exhibit 4-5. Toxicity Screening Results for Possible Non-Hazardous

Industrial Waste Constituents (continued)

Page 4-15

limited for a large proportion of the chemicals identified on the 37 lists. Nevertheless, because all chemicals

with cancer toxicity values are considered high hazard for this portion of the analysis, no chemicals would be

screened out on the basis of carcinogenicity.

 The toxicity screening reduced the number of chemicals dramatically from the original universe of over

2300. As noted above, this reduction is primarily a function of the relatively small number of chemicals (about

400) for which human or ecotoxicity data are available. The screened list contains about one-third (25/74) of the

chemicals for which CSFs were available, and about one-quarter (13/52) of those for which inhalation unit risks

are available. The chemicals with low (<50th percentile) RfDs comprise by far the largest (107) set of all the

chemicals identified by the toxicity screening, representing about one-third of the total number of chemicals for

which RfDs have been derived. A large proportion of these chemicals are pesticides. Relatively few chemicals were

identified having low inhalation RfCs and AWQCs for aquatic life.

Exhibit 4-6 summarizes the results of the screening of chemicals with regard to fate and transport

properties. The first two columns address the potential to volatilize for soil and water, as indicated by the

vapor pressure and Henry’s Law constant. Since these parameters are directly related, the chemicals in these two

columns overlap substantially. The next column lists chemicals with soil or water column degradation constants

less than 0.5/year. Since the values for these two media are close for most of the chemicals, separate columns are

not provided for each medium. The final three columns identify the chemicals with relatively high aquatic BCFs,

beef biotransfer factors, or Kows. Since all three of these values are related to partitioning between lipid and

water phases, the chemicals in these three columns also overlap substantially.

As was the case for the toxicity screens, consistently-derived fate and transport parameters are not

available to screen the majority of the chemicals. Thus, the menu of chemicals that are identified by the

screening criteria related to each individual parameter again is determined primarily by the availability of data. 

In the case of the fate and transport screening, fewer chemicals are identified as being potentially hazardous. In

addition, the fate and transport screening identifies a smaller proportion of the chemicals for which data are

available. In all cases, the chemicals exceeding the screening criteria represent less than 10 percent of the

chemicals for which data are available.

4.3.4 Release Volume Screening of Possible Non-Hazardous Industrial Waste Constituents

Chemicals not screened out by the toxicity or fate and transport criteria were screened against the 1994

TRI data (used as a proxy for occurrence in wastes). The results of this final screening are presented in Exhibit

4-7. Of the 151 unique chemicals or classes of chemicals that were identified in the toxicity or fate and transport

screening, TRI release data were available for 24 of them. Five of these chemicals (Freon 113, 1,3-butadiene,

chlorine dioxide, chloroprene, and propylene dioxide) had TRI releases above one million pounds in 1994. Nineteen

of the chemicals had TRI releases less than a million pounds. This latter group of chemicals were eliminated from

further analysis. As noted previously, the remaining 132 chemicals for which no TRI data were available were

retained in the analysis.
Page 4-16

Exhibit 4-6. Persistence and Bioconcentration/Bioaccumulation Screening Results

for Possible Non-Hazardous Industrial Waste Constituents

Vapor Pressure > 1.3x10 atm Henry'sLaw Constant > 10 atm-m /mole years -3 -5 3

Soil/Water Degradation

Rate Constant < 0.5

-1

2-Chlorophenol 2-Chlorophenol 3-Methylcholanthrene

Chloroprene Bis(2-chloroisopropyl) ether Kepone

cis-1,3-Dichloropropene Chloroprene Quintozene

Ethyl methacrylate cis-1,3-Dichloropropene

Freon 113 Dinitrobutyl phenol

Methacrylonitrile Ethyl methacrylate

N-Nitrosodi-n-propylamine Freon 113

N-Nitrosodiethylamine Methacrylonitrile

N-Nitrosomethylethylamine N-Nitrosodi-n-butylamine

N-Nitrosodi-n-propylamine

Quintozene

Safrole

Tris(2,3-dibromopropyl) phosphate

Fish BCF > 1,000 l/kg > 7.8x10 Kow > 10

Beef Biotransfer Factor

-4 5

3-Methylcholanthrene 3-Methylcholanthrene 3-Methylcholanthrene

Chlorobenzilate Diethylstilbestrol Diethylstilbestrol

Diallate Hexachlorophene Hexachlorophene

Diethylstilbestrol Kepone Kepone

Kepone Quintozene
Page 4-17

Exhibit 4-7

Screening of High-Toxicity, Persistent, Bioaccumulative/Bioconcentrating

Possible Non-Hazardous Industrial Waste Constituents Against TRI Release Volumes
Page 4-18

Exhibit 4-7 (continued)

Screening of High-Toxicity, Persistent, Bioaccumulative/Bioconcentrating

Possible Non-Hazardous Industrial Waste Constituents Against TRI Release Volumes
Page 4-19

Exhibit 4-7 (continued)

Screening of High-Toxicity, Persistent, Bioaccumulative/Bioconcentrating

Possible Non-Hazardous Industrial Waste Constituents Against TRI Release Volumes
Page 4-20

4.3.5 Summary of Possible Non-Hazardous Industrial Waste Constituents

Exhibit 4-8 summarizes the results of the TRI screening process. It places the possible non-hazardous

waste constituents into the same chemical categories as were used to characterize the known non-hazardous

industrial waste constituents in Exhibit 4-2. The largest number of possible waste constituents (74) are

pesticides and related compounds. As discussed in Section 4.3.2, these chemicals are identified as being

potentially hazardous primarily by virtue of low RfDs, although there are also some potent ecotoxins, as well as

persistent and bioaccumulative chemicals, among this group. 

The next most numerous category among the possible constituents are the other semivolatile organic

chemicals. This diverse group includes chemicals recognized both for their toxicity and their fate and transport

properties. Twelve metals/inorganic elements or groups are identified including five different thallium salts. 

Similarly, the other volatile organics group includes 5 nitrosamines among a total of 13 compounds. Also included

in this group are two very toxic organometallic compounds, methyl mercury and tetraethyllead. Among the seven

chlorinated organics are two of the five chemicals with TRI releases greater than one million pounds (Freon 113 and

chloroprene). No other chemical category is represented by more than five chemicals.

4.4 Combine and Screen Known and Possible Non-Hazardous Industrial Waste Constituents

In this section, the known (from Section 4.2) and possible (from Section 4.3) non-hazardous industrial

waste constituents are combined and screened against toxicity, fate, and transport criteria. Unlike the prior

section, screening is oriented more toward groups of chemicals rather than toward individual chemicals, and toward

comparing the properties of known versus possible non-hazardous industrial waste constituents. There is, in

addition, another screening step related to potential for occurrence in wastes, namely, comparison to 1994 nonconfidential TSCA production volume data.

4.4.1 Combine the Lists

The lists of known and possible non-hazardous industrial waste constituents are shown in Exhibits 4-2 and

4-8. Exhibit 4-9 summarizes the screening of the known non-hazardous industrial waste constituents in the same

way that Exhibit 4-7 provides these data for the possible constituents. As seen in these exhibits, the

distribution of chemicals within chemical classes is somewhat different between the known and possible nonhazardous industrial waste constituents. These differences, however, are exaggerated by the removal of the known

constituents from consideration as possible constituents. (Logically, a chemical cannot be both a “known” and

“possible” waste constituent.) The known non-hazardous industrial waste constituents are distinguished by a

relatively high proportion of metals and inorganics, chlorinated volatile organics, other volatile organics, and

polycyclic aromatic hydrocarbons, compared to the possible non-hazardous waste constituents. In contrast,

pesticides and related compounds constitute a much higher proportion of the possible non-hazardous industrial

waste constituents than the known constituents.

The pattern of differences in chemical category can be partially explained by the differences in the data

sources. The relatively high prominence of volatile organics among the possible constituents probably reflects

the difficulties in controlling fugitive releases of these high-volume chemicals during storage and processing. 

Such chemicals are somewhat less likely to turn up in groundwater samples (in the release descriptions or in

aqueous effluents) because of their high volatility. The prominence of the less volatile organics in the known

non-hazardous industrial waste constituents again reflects the greater stability of these chemicals in solid and

liquid wastes.
Page 4-21

Exhibit 4-8

Possible Non-Hazardous Industrial Waste Constituents by Chemical Class
Page 4-22

Exhibit 4-9

Screening of Known Non-Hazardous Industrial Waste Constituents

Against TRI Release Volumes
Page 4-23

Exhibit 4-9 (continued)

Screening of Known Non-Hazardous Industrial Waste Constituents

Against TRI Release Volumes
Page 4-24

Exhibit 4-9 (continued)

Screening of Known Non-Hazardous Industrial Waste Constituents

Against TRI Release Volumes
 This number includes both unique compounds (e.g., ethylbenzene) and categories of compounds (e.g., antimony compounds). 10

 The list of endocrine disrupting chemicals was developed based on information from Colborn, T., F.S. Saal, and A.M. Soto, 11

1993, "Developmental Effects of Endocrine-Disrupting Chemicals in Wildlife and Humans," Environmental Health Perspectives,

101:378-384, October 1993; and Warhurst, M., 1996, Introduction to Hormone Disrupting Chemicals, on the World Wide Web at

http://www.ed.ac.uk/~amw/oestrogenic.html.

Page 4-25

Exhibit 4-9 also shows that the known waste constituents include a much higher number of chemicals with

TRI release values greater than one million pounds (45) than is found among the possible constituents (5). This 10

is primarily due to the fact that the known waste constituents were identified first. Many of the high TRI release

chemicals also would have been identified as possible non-hazardous industrial waste constituents if they had not

been identified as known constituents. The implications of these findings for the potential severity of gaps in

the hazardous characteristics are discussed in more detail in Chapter 10.

In the analysis that follows, the known and possible non-hazardous industrial waste constituent lists are

combined, and screened against single and multiple parameters related to toxicity, fate and transport, and release

potential.

4.4.2 Screen Combined List Against Single Criteria

Quantitative Human Toxicity Indicators. Exhibit 4-10 summarizes the toxicological properties of the

combined known and possible non-hazardous industrial waste constituents. The chemicals are screened using the

same criteria as described for the possible constituents alone in Section 4.3, with the exception that additional

criteria related to carcinogenic potency are added (oral CSF and inhalation UR > 50th percentile). The list of

suspect carcinogens (i.e., the first and third columns in Exhibit 4-10) contains a large proportion of all

chemicals for which EPA has developed CSFs and URs. The proportion of the chemicals with high CSFs or URs (i.e.,

the second and fourth columns) is likewise very near to one-half of the total suspect carcinogens. This finding

indicates that, as expected, the large universe of chemicals initially screened contains almost all of the

chemicals that EPA has evaluated as potential human carcinogens. Many classes of chemicals (inorganics, volatile

chlorinated organics, pesticides, other volatile chemicals) are represented among the suspect carcinogens.

Ecotoxicity. As shown in the last column of Exhibit 4-10, 18 of the combined known and possible

constituents have low AWQCs (below 50th percentile), indicating the potential for adverse effects on aquatic

organisms. Many of these chemicals are pesticides, and most of the pesticides are persistent chlorinated

pesticides. Although most of these chemicals are no longer produced, their presence among the known non-hazardous

industrial waste constituents may give rise for some concern. Also included in this group are selenium, silver,

and hydrogen sulfide.

Potential Endocrine Disruptors. Because of the rapidly-evolving state of knowledge regarding chemicals

that may act as endocrine disruptors, estrogen inhibitors, or have other hormone-like effects, it is difficult to

estimate precisely how many of the combined known and possible non-hazardous industrial waste constituents fall

into this category. Based on the rather broad list of potential endocrine disruptors, 23 of the combined 11

constituents are implicated as being potential endocrine disruptors (Exhibit 4-11). (Nine of the TC analytes are

also potential endocrine disruptors.) Because of the lack of knowledge concerning dose-response relationships

for exposures to single and multiple
Page 4-26

Exhibit 4-10 Toxicity Summary of Known and Possible Non-Hazardous Industrial Waste Constituents
Page 4-27

Known and Possible Constituents TC Analytes

2,3,7,8-tetrachlorodibenzodioxin (2378-TCDD) cadmium

2,4,5-trichlorophenoxyacetic acid (2,4,5-T) heptachlor and heptachlor expoxide

alachlor lead

aldicarb lindane

b-hexachlorocyclohexane (b-BHC) mercury

butylbenzylphthalate (BBP) methoxychlor

DDD pentachlorophenol (PCP)

DDE toxaphene

DDT

dibromochloropropane (DBCP)

dibutyl phthalate (DBP)

dieldrin

diethylhexyl phthalate (DEHP)

dimethyl phthalate (DMP)

dioctyl phthalate (DOP)

endosulfan

mirex

parathion

polychlorinated biphenyls (PCBs)

polychlorinated dibenzodioxins (PCDDs)

styrene

Exhibit 4-11

Potential Endocrine Disruptors

endocrine disruptors, it is difficult to predict if these chemicals would present risk to humans and non-human

receptors. Nevertheless, the fact that so many of these chemicals are present among the constituents may cause

concern.

Potential for Frequent Occurrence in Wastes. The combined list of known and possible non-hazardous

industrial waste constituents were also searched to identify those chemicals with high potential for occurrence in

wastes, as indicated by TRI releases and/or non-confidential TSCA Inventory production data. The results of this

analysis are summarized in Exhibit 4-12. Constituents are included in the table only if either TRI release data or

non-CBI TSCA inventory data are available for them.

Volatility and Persistence. As discussed in Section 3.5, volatility and persistence appear to be key

indicators of potential risks for the TC analytes. In the first four columns of Exhibit 4-13, the known and

possible non-hazardous industrial waste constituents are screened against these properties. Vapor pressure of

1.3x10 atmosphere (which is approximately equivalent to 1 mm Hg) is used to identify volatile chemicals. This -3

measure approximates the potential to volatilize; many chemicals with lower vapor pressure could volatilize

readily under certain waste management conditions. Even so, 70 known or possible non-hazardous industrial waste

constituents fall into this category. This
Page 4-28

Exhibit 4-12 TRI Releases and Non-Confidential TSCA Production Volume Data for the Known and Possible NonHazardous Industrial Waste Constituents
Page 4-29

Exhibit 4-13 Volatility, Persistence, and Bioaccumulation/Bioconcentration Summary Potential of Known and Possible Non-Hazardous Industrial Waste

Constituents
Page 4-30

finding suggests that, as for the volatile TC analytes, volatilization releases and inhalation exposures (and

possibly indirect exposures) may be a concern for some of these chemicals.

Two chemicals, both chlorinated organics, are identified as having long half-lives (greater than 0.15

year) in air. This finding does not mean that all of the other constituents are too short-lived to be of concern

through air exposures. Half-lives on the order of a few hours or days also may be of concern in terms of direct

inhalation exposures. This criterion is more indicative of the potential for long-range (e.g., regional or

global-scale) transport of these chemicals in the vapor phase. Also, as noted in Section 3.5, the air half-lives

of many of the inorganic waste constituents (especially the metals) bound to particulates would also be limited

only by how long the particles remained suspended in the atmosphere.

The third column of Exhibit 4-13 identifies the non-hazardous industrial waste constituents that are

relatively persistent either in soils or in the water column. The metals all fall into this category, along with

the PAHs, many chlorinated pesticides, and 2,3,7,8-TCDD. The only volatile organic chemical in this category is

1,2-dichloropropane. Appearance in this category arouses concern for potential inhalation and indirect pathway

exposure risks, as discussed in Section 3.5.

A high Kow, as indicated in the fourth column, indicates a high potential to bind to soil organic matter. 

It is highly correlated with the tendency to bioaccumulate. Thirty-one of the known and possible waste

constituents including many persistent pesticides and PAHs, are in this category.

Bioaccumulation Potential. The last three columns of Exhibit 4-13 indicate the potential for

bioaccumulation by the known and possible non-hazardous industrial waste constituents in aquatic and terrestrial

food chains. The constituents with aquatic BCFs or BAFs greater than 1,000 are limited to the chlorinated

pesticides, several phthalate esters, and diethylstilbestial (DES). This finding does not imply that no other

constituents present significant risks through indirect pathways; nevertheless, the identified chemicals are all

clearly recognized as being problematic from the point of view of bioconcentration. If these chemicals were

released in significant amounts from non-hazardous waste industrial management activities, they could present

substantial risks through food-chain exposures.

The last column of the table lists chemicals that are taken up from feed by beef cattle with above-average

(greater than 75th percentile) efficiency. This list includes most chemicals that also are of potential concern

for aquatic ecosystems. Also, several additional classes of chemicals are identified, including the metals and

PAHs. Although the beef biotransfer factor is only one of many parameters determining the potential for risks to

humans from beef consumption, it is a reasonable indicator of potential concern for this pathway and is a useful

indicator of exposure potential in other terrestrial food chains.

LNAPL and DNAPL Formation. The potential to form nonaqueous phase liquids (NAPLs) is of great concern

from the point of view of waste management risks. Historically, NAPLs have been serious problems in the

remediation of hazardous waste, because of their high potential risks and high remediation costs. Any chemical

that is relatively insoluble in water and is a liquid at ambient temperature can be the principal component of a

NAPL. If the chemical or chemical mixture is denser than water, then a dense nonaqueous phase liquid (DNAPL) is

formed. If the liquid is less dense than water, a light nonaqueous phase liquid (LNAPL) may be formed.
 U.S. Environmental Protection Agency, Office of Solid Waste and Emergency Response, Evaluation of the Likelihood of DNAPL 12

Presence at NPL Sites, EPA 540-R-93-073, September 1993.

 BTEX refers to benzene, toluene, ethylbenzene, and xylene, which are common constituents of gasoline. 13

Page 4-31

DNAPLs are of particular concern because, when they escape to groundwater, they will sink through the

unsaturated zone or aquifer until they encounter bedrock or another barrier. They can remain at the bottom of the

aquifer (for example, in bedrock fractures) where they are hard, or in some cases nearly impossible, to remediate. 

Most DNAPLs undergo only limited degradation in the subsurface, and persist for long periods while slowly

releasing soluble organic constituents to groundwater. Even with a moderate DNAPL release, dissolution may

continue for hundreds of years or longer under natural conditions before all the DNAPLs are dissipated and

concentrations of soluble organics in groundwater return to background levels. When released into surface water,

DNAPLs tend to sink to the bottom and contaminate sediments. LNAPLs, in contrast, will tend to float on the surface

of an aquifer, where they are easier to remedy; yet, they also can contaminate large volumes of groundwater through

slow dissolution. Both LNAPLs and DNAPLs also can facilitate the transport of toxic waste constituents by

solubilizing chemicals that would otherwise be immobile in waste or soil matrices.

It is difficult to predict the circumstances under which LNAPL and DNAPL formation will occur and pose a

risk to human health or the environment. Whether significant amounts of NAPLs will form depends on the composition

of the wastes and the management practices employed. Reports of nonaqueous phase liquids were not found among the

release descriptions for non-hazardous industrial waste management summarized in Chapter 2, possibly due to

limitations in monitoring requirements. EPA has recently conducted a study of the potential for DNAPL formation

at hazardous waste (NPL) sites, and identified several industries where NAPL formation is particularly likely to

occur. These industries include wood treating sites, general manufacturing, organic chemical production, and 12

“industrial waste landfills”. A wide variety of chemicals have been found in NAPLs, and it appears that if a

chemical is to be the major constituent of a NAPL, the most important requirements are relative insolubility in

water and liquidity at ambient temperatures.

Exhibit 4-14 identifies a number of the known and possible non-hazardous industrial waste constituents

with the requisite physical properties. Since there is no clear dividing line between chemicals likely and not

likely to form NAPLs, this list was developed using a combination of professional judgment and information about

the physical properties of the waste constituents. All of the chemicals listed are organics, have relatively low

water solubilities, and are liquid at room temperature (melting points greater than 7oC, boiling point greater

than 30oC). Those indicated as being potential DNAPL formers have bulk liquid densities greater than 1 gm/cc,

while those with densities less than water are indicated as potential LNAPL formers. The distinction is not clearcut however, as a mixture of light and heavy constituents at different relative concentrations might have widely

varying densities.

Exhibit 4-14 identifies more potential DNAPL formers than LNAPL formers found among the known and

possible waste constituents. Based on density considerations, the LNAPL formers tend to be primarily the nonhalogenated hydrocarbons, including “BTEX” and compounds with similar properties, whereas the DNAPL formers tend 13

to be primarily chlorinated and brominated chemicals. Not included in the NAPL list are pesticides that also

fulfill the physical criteria, but which are no longer produced (see Chapter 9) and thus are less likely to be

present in significant amounts in pure form in non-hazardous industrial wastes. These findings suggest that, on

physical bases alone, many
 U.S. Environmental Protection Agency, Office of Solid Waste and Emergency Response, Evaluation of the Likelihood of DNAPL 14

Presence at NPL Sites, EPA 540-R-93-073.

Page 4-32

Exhibit 4-14

LNAPL/DNAPL Formation Potential of Known

and Possible Non-Hazardous Industrial Waste Constituents

Chemical Name NAPL Type Chemical Name NAPL Type a a

1,1,1,2-Tetrachloroethane D Chloropropene D

1,1,1-Trichloroethane D cis-1,2-Dichloroethylene D

1,1,2-Trichloropropane D cis-1,3-Dichloropropene D

1,1,2,2-Tetrachloroethane D Cumene L

1,1,2-Trichloroethane D Di(2-ethylhexyl) phthalate L

1,2,3-Trichloropropane D Dibutyl phthalate D

1,2-Dibromo-3-chloropropane D Dichlorobromomethane D

1,2-Dibromoethane D Diethyl phthalate D

1,2-Dichlorobenzene D Dimethyl phthalate D

1,2-Dichloroethylene, trans D Ethylbenzene L

1,2-Dichloropropane D Ethylidene Dichloride D

1,3-Dichloropropylene D Freon 113 D

2,3-Dichloropropanol D Hexachlorocyclopentadiene D

2,3,4,6-Tetrachlorophenol D n-Dioctylphthalate L

2,4-Dichlorophenol D N-Nitrosodi-n-propylamine L

2-Chloroacetophenone L p-Chloroaniline D

Acetophenone L Propylene oxide L

Allyl chloride L Safrole L

Benzyl chloride D Styrene L

Bromoform D Toluene L

Butyl benzyl phthalate D trans-1,3-Dichloropropene D

Carbon disulfide D Trichlorofluoromethane D

Chlorodibromomethane D Xylene (mixed isomers) L

Notes:

re compound > 1.0 gm/cc) D = DNAPL (density of pu a

 L = LNAPL (density of pure compound < 1.0 gm/cc)

of the known and possible non-hazardous industrial waste constituents could form LNAPLs or DNAPLs. As noted

above, however, when this actually occurs depends to a large degree on the specific characteristics of the wastes

and waste management practices.

EPA's analysis of DNAPL formation at NPL sites found that the contaminants most directly associated with

DNAPL presence include creosote compounds, coal tar compounds, polychlorinated biphenyls (PCBs), chlorinated

solvents, and mixed solvents.14
Page 4-33

4.4.3 Screen Combined List Against Multiple Parameters

This section discusses the results of one last round of screening conducted on the entire combined list of

known and possible non-hazardous industrial waste constituents. This analysis combines toxicity, persistence,

volatility, and bioaccumulation screens in various combinations in order to identify the chemicals most likely to

pose risks by various exposure pathways. Only constituents in the intersections of the screens remain (e.g., only

constituents that are persistent and highly toxic). For human toxicity, the criteria have been applied in the

following order:

Persistent and Highly Toxic to Humans. This combination is intended to identify highly

toxic chemicals that could pose risks through any pathways involving long-term release

and transport of contaminants, such as groundwater and indirect pathways involving air,

surface water, or groundwater releases. 

Persistent, Highly Toxic to Humans and Bioaccumulative. This screen narrows the above

waste constituents to those with potential for adverse effects through indirect food

chain exposure.

Persistent, Highly Toxic to Humans, Bioaccumulative, and Volatile. This combination

further narrows the above chemicals to those with potential to cause indirect pathway

risks through air releases.

A fourth screen applied persistent, ecotoxic, and bioaccumulative criteria to the combined list of constituents. 

This combination of screening criteria is intended to identify chemicals for which potential harm to ecological

receptors is a potential concern.

The individual criteria used in combination are described in Section 4.3. The persistence screen

consisted of a determination of whether the chemicals had soil or water column degradation rate constants of less

than 0.5/year. “Highly toxic” indicates any chemical having a CSF or Unit Risk above the 50th percentile of all

chemicals, or a chronic RfD below the 50th percentile. Volatility was screened against Henry's Law constant of 10-5

atm-m /mole, and bioaccumulation potential determined by an aquatic BCF or BAF value of greater than 1,000 L/Kg. 3

The results of the combined screening of known and possible non-hazardous industrial waste constituents

are summarized in Exhibit 4-15. To a substantial degree, these results parallel the screening-level modeling

results for the TC analytes discussed in Section 3.5. Four of the nine persistent and highly toxic chemicals are

chlorinated pesticides or degradation products, along with three metals (antimony, beryllium, and molybdenum),

benzo(a)pyrene, and 2,3,7,8-TCDD. The appearance of benzo(a)pyrene suggests that other high molecular weight

PAHs (some of which are also carcinogens) might also pass this screen if CSF values were available for these

compounds. In addition, several other chlorinated pesticides have properties that just miss the toxicity or

persistence cutoff values.

When bioaccumulation potential is added to the screening conditions (second column of Exhibit 4-15), no

chemicals drop out. This finding shows the high correlation between persistence and bioaccumulative potential: 

if a chemical was not persistent, it would lack the opportunity to accumulate in environmental media or tissue.
Page 4-34

Exhibit 4-15

Multiple Screening Criteria Applied to Known

and Possible Non-Hazardous Industrial Waste Constituents

Persistent and Highly Toxic Bioaccumulative Bioaccumulative Bioaccumulative

Persistent, Highly Persistent, Highly Persistent,

Toxic, and Toxic, and Ecotoxic, and

Volatile,

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD)2,3,7,8-TCDD Aldrin 2,3,7,8-TCDD

Aldrin Aldrin DDE DDT a

Antimony Antimony DDT Dieldrin

Benzo[a]pyrene Benzo[a]pyrene

Beryllium Beryllium

DDE DDE

DDT DDT a

Dieldrin Dieldrin

Molybdenum Molybdenum

a

a

a

a

a

Notes:

elled under FIFRA. Use has been canc a

When the criterion of volatility is added to the preceding screens, three chemicals, all persistent

pesticides remain. This result again parallels the results seen for the TC analytes in Section 3.5. If vapor

pressure cutoff (1 mm Hg), rather than Henry’s Law constant (10 atm.-M /mole) is used to characterize the -5 3

potential to volatilize, none of the chemicals qualify in this category.

The last column of Exhibit 4-15 identifies persistent, bioaccumulative, and ecotoxic chemicals. As might

be expected from the previous screening results, these chemicals include chlorinated pesticides and 2,3,7,8-TCDD. 

Because the AWQC screen is based only on harmful concentrations, it does not include any screening for the

concentrations normally encountered in the environment. Thus, if a much less toxic chemical (for example zinc or

copper) were released into the environment in much larger amounts than the pesticides, the exposure concentrations

might be much greater and adverse effects on ecological receptors might occur.

4.5 Driving Risk Pathways for the Known and Possible Non-Hazardous Industrial Waste Constituents

EPA has previously evaluated the potential risks associated with the management of many known and

possible non-hazardous industrial waste constituents in the context of deriving proposed risk-based exit levels

for the proposed HWIR-Waste rulemaking. As discussed in Section 3.5, these proposed exit levels were derived by

back-calculating concentrations in wastewaters and nonwastewaters corresponding to acceptable risk levels. The

magnitude of the modeled exit levels is inversely proportional to the magnitude of risk posed by the chemical when

placed in the specified management units. Proposed exit levels are calculated for groundwater exposures and other

pathways. Thus, the proposed exit levels also indicate the relative importance of the exposure pathways for each

chemical. 

Exhibit 4-16 tabulates the exit levels for 128 of the known or possible non-hazardous industrial waste

constituents (i.e., the entire combined list prior to any screens that were also addressed in the HWIR-waste
 The Agency is currently revising the proposed HWIR-Waste exit level risk modeling methods in response to comments from the 15

Science Advisory Board and other reviewers. Thus, the proposed exit levels shown in Exhibit 4-15 should be regarded as

preliminary.

 

16 Edelstein, Maravene, "Memorandum to Paul Tobin on the Subject of a Database of Chemicals of Interest for Short Term

Inhalation Exposure," September 1993. Sources of data for the database include the Emergency Planning and Community Right-toKnow Act (EPCRA) (40 CFR Part 355), Section 112(r) of the Clean Air Act (CAA) (40 CFR Part 68), and the Occupational Safety and

Health Administration (OSHA) Process Safety Management (PSM) Standard (29 CFR Part 1910).

Page 4-35

proposed rulemaking), and the exposure pathways that were risk drivers for setting the exit levels. As in the case

of the similar analysis for the TC analytes in Section 3.5, many of the known or possible non-hazardous industrial

waste constituents have proposed exit levels that are quite low (68 are below 0.1 mg/l). Therefore, the Agency has

determined that the presence of these constituents in wastes at even relatively low concentrations may pose

significant risks to human health. Again it should be noted that the target cancer risk level used to derive the

exit levels was 10 , rather than the 10 level used in the derivation of TC regulatory levels. Even so, these -6 -5

levels indicate potential cause for concern for many of these chemicals at even low concentrations in wastes.15

As was also the case for the TC analytes, non-groundwater pathway risks drive the establishment of exit

levels for about one-quarter of the known or possible non-hazardous industrial waste constituents. The driving

pathways include direct inhalation and vegetable and milk ingestion. Pesticides make up a large proportion of the

chemicals for which non-groundwater pathways drive the risks, but many volatile chlorinated and nonchlorinated

organics also fall into this category. Ecological, rather than human health risks, drive the setting of proposed

exit levels for two chemicals (copper and parathion). These findings confirm the indications from the toxicity

and fate and transport screening presented in the previous sections that inhalation and indirect pathways could be

of concern for many of the known or possible non-hazardous industrial waste constituents.

4.6 Potential Acute Hazards Associated With Known and Possible Non-Hazardous Industrial Waste

Constituents

To this point, the evaluation of the potential hazards associated with the possible and known nonhazardous industrial waste constituents has focused on chronic toxic effects. As discussed in Chapter 3, waste

constituents may also pose risks from acute exposures, as well as from physical hazards associated with

reactivity, flammability, or corrosivity. To investigate the possibility of acute adverse effects, the Agency has

compared list of the known and possible waste constituents to lists developed by the EPA and other regulatory

agencies that identify such hazardous properties. The results of this comparison are summarized in Exhibit 4-17.

As shown in the exhibit, 38 of the known and possible non-hazardous industrial waste constituents have

been identified in one or more regulatory contexts as being acutely toxic. Although most of these chemicals are 16

volatile organics, several acid gases and other inorganic compounds also are included. Appearance on these lists

does not automatically indicate that acute
Page 4-36

Exhibit 4-16

Lowest Proposed HWIR-Waste Exit Levels for

Known and Possible Non-Hazardous Industrial Waste Constituents
Page 4-37

Exhibit 4-16 (continued)

Lowest Proposed HWIR-Waste Exit Levels for

Known and Possible Non-Hazardous Industrial Waste Constituents
Page 4-38

Exhibit 4-16 (continued)

Lowest Proposed HWIR-Waste Exit Levels for

Known and Possible Non-Hazardous Industrial Waste Constituents
 ICF Incorporated, Draft Physical/Chemical Properties Criteria Database, October 1987. Sources of data for the database 17

include the Department of Transportation (DOT) Hazardous Materials Table (49 CFR 172.101) and the National Fire Protection

Association (NFPA) publication 325M, Fire Hazard Properties of Flammable Liquids, Gases, and Volatile Solids.

Page 4-39

Exhibit 4-17

Potential Acute Hazards Associated with Known

and Possible Non-Hazardous Industrial Waste Constituents

Acutely Toxic Chemicals HighlyFlammable Chemicals Highly Reactive Chemicals

1,1,1-Trichloroethane Furan 1,3-Butadiene 1,3,5-Trinitrobenzene

1,3-Butadiene Hydrazine Acetaldehyde 2,4,6-Trinitrotoluene

Acetaldehyde Hydrogen cyanide Chloroethane

Acrolein Hydrogen fluoride Chloromethane

Acrylonitrile Hydrogen sulfide Dimethylamine

Allyl alcohol Methacrylonitrile Ethane, 1,1'-oxybisAllyl chloride Methanol Ethylene oxide

Ammonia Methyl iodide Formaldehyde

Arsine Methyl isocyanate Furan

Bis(chloromethyl) ether Methyl mercaptan Hydrogen cyanide

Bromomethane Nickel carbonyl Hydrogen sulfide

Carbon disulfide Nitric oxide Methyl mercaptan

Chlorine Nitrogen dioxide Phosphine

Chlorine dioxide Phosgene Propylene oxide

Chloromethane Phosphine Vinylidene chloride

Epichlorohydrin Propylene oxide

Ethylene oxide Toluene

Fluorine Vinyl acetate

Formaldehyde Xylene (mixed isomers)

Notes:

orization criteria. See text for categ a

adverse effects will occur, only that such effects could potentially be associated with management of wastes

containing these chemicals.

Fifteen of the waste constituents are also identified as being highly flammable. These are mostly 17

volatile organics, along with a few inorganic gases and liquids. They substantially overlap with the previous

list. Only two of the known or possible non-hazardous industrial waste constituents are identified as being

highly reactive.
Page 4-40

4.7 Identify Individual Chemicals and Classes of Chemicals Constituting Potential Gaps

The analyses in the previous sections help to clarify the nature of potential gaps in the hazardous waste

characteristics associated with specific chemicals and chemical classes related to chronic human health risks and

ecological risks. The analyses identified groups of chemicals most likely to be present in non-hazardous

industrial waste, and screened them in terms of their toxicity, fate, and transport properties. The results of the

proposed HWIR-waste modeling were reviewed, where available, to confirm and expand the findings of the screening

results. Finally, the known and possible non-hazardous industrial waste constituents were reviewed with regard to

their potential to cause acute adverse effects. As a result of these efforts, a number of potential gaps have been

identified, as summarized in Exhibit 4-18.

This listing of potential gaps for non-TC analytes should not be taken as being either exhaustive or

definitive. These gaps are potential, not actual gaps. They have been identified for purposes of targeting

further analysis, not for purposes of choosing what constituent or wastes to regulate. Other potential gaps

related to natural resource damages and regional or global environmental problems are discussed in Chapter 5. 

Also, Chapter 6 describes how several states have expanded the TC, implicitly identifying gaps in the TC. In

Chapter 10, some of the unresolved issues identified in Exhibit 4-18 are discussed and the available information

about the potential significance of these impacts is reviewed in detail. 

EPA recognizes the limitations of this analysis. As noted previously, the data concerning the

composition of non-hazardous industrial wastes are quite limited and generally quite old. This lack of data in

large part explains the need for the elaborate screening procedures employed in this chapter. Few data are

available on the current patterns of non-hazardous industrial waste generation, management, and disposal. In

addition, the chemical-specific screening is further complicated by the lack of toxicity and fate and transport

parameter data for a large proportion of the universe of possible waste constituents, which necessitated extensive

use of professional judgment to supplement the screening process.
Page 4-41

Exhibit 4-18

Potential Gaps in the Hazardous Waste Characteristics Identified Based

on the Hazardous Properties of Known and Possible Non-Hazardous

Industrial Waste Constituents

Potential Gap Basis for Identification Gaps

ImportantUnresolved Issues, Data

Groundwater exposure to toxic Potential variability in groundwater Amounts and concentrations disposed;

metals transport; finding of metals in groundwater management practices; leaching

above HBLs in release descriptions; proposed characteristics

HWIR-waste risk results

Groundwater and inhalation Findings above HBLs in release descriptions; Amounts and concentrations disposed;

pathway exposures to volatile large number of volatiles among non-hazardousmanagement practices

chlorinated organic compounds industrial waste constituents; screeninglevel risk results; proposed HWIR-waste risk

results

Inhalation pathway exposure to Screening level risk modeling; screening basedWhether these pesticides are still

persistent organic pesticides on toxicity, fate and transport parameters being managed in substantial amounts

as non-hazardous wastes

Exposure to persistent organic Screening risk results; screening of waste Whether these pesticides are still

pesticides and some metals throughconstituents for persistence, being managed in substantial amounts

aquatic indirect pathways bioaccumulation, toxicity, proposed HWIR- as non-hazardous wastes

Waste risk results indicating non-groundwater

pathways drive risks

Risks to aquatic ecosystems from Ecotoxicity, persistence, bioaccumulation Whether these pesticides are still

persistent pesticides screening; analogy to screening risk modeling being managed in substantial amounts

as non-hazardous wastes

Risks to humans, ecological Toxicity, fate and transport screening; Amounts and concentrations managed

receptors from chlorinated analogy to screening risk results; proposed (not high-volume chemicals)

dioxins, PCBs HWIR-Waste risk results

Endocrine disruption (humans and Findings in release descriptions; Dose-responses relationships for

ecological receptors) from toxicological properties; fate and transport individual and multiple agents;

exposure to chlorinated screening combined exposures are largely

pesticides, phthalate esters unknown

Adverse effects to humans from Occurrence in release descriptions above HBLs;Amounts and concentrations disposed

exposure to “BTEX” hydrocarbonsfate and transport screening a

Groundwater exposures to phenolicOccurrence in release descriptions above HBLsRelatively low toxicity compounds;

compounds amounts and concentrations in nonhazardous wastes

Exhibit 4-18 (continued)

Potential Gaps in the Hazardous Waste Characteristics Identified Based

on the Hazardous Properties of Known and Possible Non-Hazardous

Industrial Waste Constituents
Page 4-42

Potential Gap Basis for Identification Gaps

ImportantUnresolved Issues, Data

Potential for LNAPL and DNAPL Large number of waste constituents have NAPL formation is highly dependent on

formation, primarily for physical properties consistent with NAPL waste characteristics and specific

halogenated solvents formation (mostly DNAPLs) management practices; few data are

available

Exposure to PAHs Occurrence in Subtitle D data; persistence; Amounts and concentrations disposed

toxicity screening

Acute effects; toxicity and other Many constituents are acutely toxic, highly Acute risks are highly dependent upon

injuries flammable, or highly reactive nature and composition of wastes and

management practices

Notes:

Toluene, ethylbenzene, xylenes; these compounds are all commonly found in gasoline, kerosene, and related petroleum a

products.
Page 4-43

CHAPTER 4. POTENTIAL GAPS ASSOCIATED WITH

NON-TC CHEMICALS .............................. 4-1

4.1 Overview of Methodology ................................................. 4-1

Step 1: Identify and Classify Known Non-Hazardous Industrial Waste Constituents ... 4-1

Step 2: Identify and Screen Possible Non-Hazardous Industrial Waste Constituents ... 4-1

Step 3: Apply Hazard-Based Screening Criteria ............................... 4-3

Step 4: Review Relevant Multipathway Risk Modeling Results ................... 4-3

Step 5: Identify Potential Acute Hazards ..................................... 4-3

Step 6: Summarize Findings ............................................... 4-3

4.2 Identify and Classify Known Constituents of Non-Hazardous Industrial Wastes ...... 4-3

4.3 Identify Possible Non-Hazardous Industrial Waste Constituents of Potential Concern . . 4-7

4.3.1 Approach to Identifying Potentially Hazardous Chemicals ................. 4-7

4.3.2 Screening Approach ............................................... 4-9

4.3.3 Toxicity, Fate, and Transport Screening for Possible Non-Hazardous Industrial

Waste Constituents ............................................... 4-12

4.3.4 Release Volume Screening of Possible Non-Hazardous Industrial Waste

Constituents .................................................... 4-15

4.3.5 Summary of Possible Non-Hazardous Industrial Waste Constituents ........ 4-20

4.4 Combine and Screen Known and Possible Non-Hazardous Industrial Waste Constituents4-20

4.4.1 Combine the Lists ................................................ 4-20

4.4.2 Screen Combined List Against Single Criteria .......................... 4-26

4.4.3 Screen Combined List Against Multiple Parameters ..................... 4-34

4.5 Driving Risk Pathways for the Known and Possible Non-Hazardous Industrial Waste

Constituents ........................................................... 4-35

4.6 Potential Acute Hazards Associated With Known and Possible Non-Hazardous Industrial 

Waste Constituents ...................................................... 4-36

4.7 Identify Individual Chemicals and Classes of Chemicals Constituting Potential Gaps . 4-41
Page 4-44

Exhibit 4-1 Flow Chart of Procedures Used to Identify Non-TC Chemicals Posing Potential

Gaps in the TC Characteristics ............................................. 4-2

Exhibit 4-2 Known Non-Hazardous Industrial Waste Constituents Chemicals Found in Case

Studies, ISDB, Listings Documents, Effluent Guideline Documents by Chemical

Class and Listing Documents ............................................... 4-6

Exhibit 4-3 Lists Used to Identify Possible Non-Hazardous Industrial Waste Constituents ........ 4-8

Exhibit 4-4 Criteria Considered for Screening Non-Hazardous Industrial Waste Constituents .... 4-10

Exhibit 4-5 Toxicity Screening Results for Possible Non-Hazardous Industrial Waste

Constituents ........................................................... 4-13

Exhibit 4-6 Persistence and Bioconcentration/Bioaccumulation Screening Results for

Possible Non-Hazardous Industrial Waste Constituents ......................... 4-16

Exhibit 4-7 Screening of High-Toxicity, Persistent, Bioaccumulative/Bioconcentrating

Possible Non-Hazardous Industrial Waste Chemicals Against TRI Release Volumes . 4-17

Exhibit 4-8 List of Known and Possible Non-Hazardous Industrial Waste Constituents By

Chemical Class ......................................................... 4-21

Exhibit 4-9 Screening of Known Non-Hazardous Industrial Waste Constituents Against TRI

Release Volumes ....................................................... 4-22

Exhibit 4-10 Toxicity Summary of Known and Possible Non-Hazardous Industrial Waste Constituents4-27

Exhibit 4-11 Potential Endocrine Disruptors ............................................ 4-28

Exhibit 4-12 TRI Releases and TSCA Production Volume Data for the Known and Possible Non-Hazardous

Industrial Waste Constituents ............................................. 4-29

Exhibit 4-13 Volatility, Persistence, and Bioaccumulation/Bioconcentration Potential of Known and

Possible Non-Hazardous Industrial Waste Constituents ......................... 4-30

Exhibit 4-14 LNAPL/DNAPL Formation Potential of Known and Possible Non-Hazardous Industrial

Waste Constituents ...................................................... 4-33

Exhibit 4-15 Multiple Screening Criteria Applied to Known and Possible Non-Hazardous

Industrial Waste Constituents ............................................. 4-35

Exhibit 4-16 Lowest Proposed HWIR-Waste Exit Levels for Known and Possible Non-Hazardous

Industrial Waste Constituents ............................................. 4-37

Exhibit 4-17 Potential Acute Hazards Associated with Known and Possible Non-Hazardous

Industrial Waste Constituents ............................................. 4-40

Exhibit 4-18 Potential Gaps in the Hazardous Waste Characteristics Identified Based on the

Hazardous Properties of Known and Possible Non-Hazardous Industrial Waste

Constituents ........................................................... 4-42
Release 

Descriptions ISDB Data Listing

Documents

Effluent

Guidelines

Development

Documents Known NonHazardous Industrial

Waste Constituents

Exhibits 4-2, 4-9

Regulatory, Advisory Lists

Exhibit 4-3

Screen Against

Single Toxicity and Fate 

and Transport Criteria

Exhibits 4-4, 4-5, 4-6

Screen Against TRI 

Release Data

Exhibit 4-7

Possible NonHazardous Industrial 

Waste Constituents

Exhibit 4-8

Known and Possible 

Non-Hazardous Industrial

Waste Constituents 

Screen Against 

Single and Multiple 

Toxicity, Fate and

Transport, Persistence, and

Bioaccumulation

Criteria, TSCA

Production Volumes

Exhibits 4-10, 4-12, 4-13, 4-15

Identify Potential

Endocrine Disrupters 

Exhibit 4-11

Identify Potential

LNAPL, DNAPL

Formers 

Exhibit 4-14

Identify HWIRWaste Risk Driving

Exposure Pathways

Exhibit 4-16

Identify Acutely Hazardous,

Ignitable, Corrosive,

and Reactive Constituents

Exhibit 4-17

Identify Individual Chemicals 

and Classes of Chemicals

Constituting Potential Gaps

Exhibit 4-18

Step 5: Acute Hazards

Step 6: Summary

Step 4: Multipathway Risk Modeling

Step 3: Hazard Based Screening Criteria

Step 2: Possible Non-Hazardous

Industrial Waste Constituents

Step 1: Known Non-Hazardous 

Industrial Waste Constituents

c6n020-1

Exhibit 4-1 Flow Chart of Procedures Used to Identify Non-TC Chemicals Posing

 Potential Gaps in the TC Characteristics

Page 4-2
EXHIBIT 4-2 KNOWN NON-HAZARDOUS INDUSTRIAL WASTE CONSTITUENTS FOUND IN CASE STUDIES, ISDB, LISTINGS DOCUMENTS, AND EFFLUENT GUIDELINES BY CHEMICAL CLASS

Metals/ Inorganics

Volatile Chlorinated 

Organics Volatile Hydrocarbons Other Volatile Organics

Pesticides/ Intermediates/ Degradation 

Products Phthalate Esters

Phenolic 

Compounds

Polycyclic Aromatic 

Hydrocarbons Other Semivolatile Organics

Aluminum (fume or dust) 1,1,1,2-Tetrachloroethane 1,2,4-Trimethylbenzene 1,2-Dibromoethane 2,3,4,6-Tetrachlorophenol Butyl benzyl phthalate 2,4-Dimethylphenol 2-Methylnaphthalene 1,2-Diphenylhydrazine

Ammonia 1,1,1-Trichloroethane Cumene 1,4-Dioxane Aldicarb Di(2-ethylhexyl) phthalate 2,4-Dinitrophenol 7,12-Dimethylbenz[a]anthracene 2,3,7,8-TCDD

Antimony 1,1,2,2-Tetrachloroethane Ethylbenzene 2-Ethoxyethanol Aldrin Dibutyl Phthalate 2-Nitrophenol Acenaphthene 2,4-Diaminotoluene

Beryllium 1,1,2-Trichloroethane m-Xylene 2-Ethoxyethanol acetate alpha-Endosulfan Diethyl Phthalate 4,6-Dinitro-o-cresol Acenaphthylene 2,4-Dichlorophenol

Boron and compounds 1,2,3-Trichloropropane n-Butylbenzene 2-Hexanone alpha-Hexachlorocyclohexane Dimethyl Phthalate 4-Nitrophenol Anthracene 2,6-Dinitrotoluene

Calcium 1,2,4,5-Tetrachlorobenzene n-Propyl benzene 2-Methoxyethanol Atrazine n-Dioctyl phthalate p-Chloro-m-cresol Benz[a]anthracene 3,3'-Dimethoxybenzidine

Calcium Carbonate 1,2,4-Trichlorobenzene o-Xylene 2-Methyllactonitrile beta-BHC Phenol Benzo(a)phenanthrene 4-Aminobiphenyl

Carbon dioxide 1,2-Dibromo-3-chloropropane p-Xylene 2-Methylpyridine beta-Endosulfan Phenolics Benzo(a)pyrene 4-Aminopyridine

Chloride 1,2-Dichlorobenzene sec-Butylbenzene 2-Nitropropane Carbofuran Benzo(k)fluoranthene 5-Nitro-o-toluidine

Chlorine 1,2-Dichloroethylene Styrene Acetaldehyde DDE Benzo[b]fluoranthene Acetophenone

Cobalt 1,2-Dichloropropane Toluene Acetone DDT/DDD Benzo[ghi]perylene Acrylamide

Copper 1,3-Dichlorobenzene Xylenes Acetonitrile Diazinon Dibenz[a,h]anthracene Acrylic acid

Copper cyanide 1,3-Dichloropropylene Acrolein Dieldrin Fluoranthene Adipic acid

Cyanides (sol. salts/complexes) Allyl chloride Acrylonitrile Dimethoate Fluorene Aniline

Cyanogen chloride Benzoic trichloride Allyl alcohol Disulfoton Indeno(1,2,3-cd)pyrene Benzal chloride

Fluoride/fluorine/hydrogen fluoride Bis(2-chloroethyl) ether Benzenethiol Endosulfan Isophorone Benzoic acid

Fluorine Chlorobromomethane Benzyl alcohol Endosulfan sulfate Methapyrilene Benzyl chloride

Hydrogen cyanide Chlorodibromomethane Bromoform Endothall Pyrene Biphenyl

Hydrogen fluoride Chloroethane Bromomethane Endrin aldehyde Coal tars

Hydrogen sulfide Chloromethane Carbon disulfide Endrin ketone Creosote

Iron cis-1,2-Dichloroethylene Crotonaldehyde Fampur Dibenzofuran

Magnesium Dichloro-2-propanol, 1,3- Cyclohexanol Mesitylene Dichlorobenzene (mixed isomers)

Manganese Dichlorobromomethane Cyclohexanone Methyl iodide Diphenyl ether

Molybdenum Dichlorodifluoromethane Dimethylamine Methyl parathion Diphenylamine

Nickel Dichloroethylene, N.O.S. Dimethyl sulfate Molinate Ethyl dipropylthiocarbamate

Nickel carbonyl Dichloromethane Dimethylamine O,O-Diethyl O-pyrazinyl phosphorothioate Formic acid

Nitrates/nitrites Dichloropropane Ethane, 1,1'-oxybis- Parathion m-Dinitrobenzene

Nitric oxide Epichlorohydrin Ethyl acetate Phorate Maleic anhydride

Nitrite Ethyl chloride Ethylene glycol Sulfotep Maleic hydrazide

Nitrogen Ethylidene Dichloride Ethylene oxide N-Nitroso-dimethyl amine

Nitrogen dioxide Hexachlorocyclopentadiene Formaldehyde N-Nitrosodiphenyl amine

Phosgene Pentachloroethane Furan Naphthalene

Phosphine Tetrachloroethane, N.O.S. Furfural Nitrosamine, N.O.S.

Phosphorus trans-1,2-Dichloroethylene Hydrazine O-Chlorotoluene

Potassium trans-1,3-Dichloropropene Isobutyl alcohol Ortho(2-)Nitroaniline

Silica Trichloroethane Malononitrile p-Chloroaniline

Silicon Trichlorofluoromethane Methanol p-Chlorotoluene

Sodium Trichloromethanethiol Methyl isobutyl ketone p-Nitroaniline

Sodium cyanide Methyl isocyanate Pentachlorobenzene

Strontium Methyl mercaptan Phenanthrene

Sulfide Methyl methacrylate Phthalic acid

Sulfite Methylene bromide Phthalic anhydride

Thallium n-Butyl alcohol Polychlorinated biphenyls

Tin (total) Urethane Resorcinol

Titanium Vinyl acetate Thioacetamide

Vanadium (fume or dust) Thiram

Vanadium pentoxide

Zinc

Total: 48 38 12 45 29 6 8 18 46

4-2.txt
EXHIBIT 4-7 SCREENING OF HIGH-TOXICITY, PERSISTENT, BIOACCUMULATIVE/BIOCONCENTRATING

POSSIBLE NON-HAZARDOUS WASTE CONSTITUENTS AGAINST TRI RELEASE VOLUMES

Chemical CAS Chemical Name

Release 

Volume

Oral CSF

Inhalation Unit Risk

Oral RfD < 50th

RfC < 50th

AWQC (Chronic) < 50th

Degradation Rate for Water Column

Fish BCF

Henry's Law Constant

Kow

Soil Degradation Rate

Vapor Pressure > 1_3e-3

Beef Biotransfer Factor >7_8e-4

0000076-13-1 Freon 113 5,077,542 ✔ ✔

0000106-99-0 1,3-Butadiene 2,711,287 ✔

0010049-04-4 Chlorine dioxide 1,501,041 ✔

0000126-99-8 Chloroprene 1,157,755 ✔ ✔

0000075-56-9 Propylene oxide 1,076,879 ✔ ✔

0000101-68-8 Methylenebis(phenylisocyanate) 846,938 ✔

0000103-23-1 Bis(2-ethylhexyl) adipate 844,594 ✔

0001163-19-5 Decabromodiphenyl oxide 469,811 ✔

0001332-21-4 Asbestos (friable) 294,368 ✔

0000126-98-7 Methacrylonitrile 80,802 ✔ ✔ ✔

0026471-62-5 Toluenediisocyanate (mixed isomers) 50,695 ✔

0000092-87-5 Benzidine 31,606 ✔ ✔ ✔

0000121-69-7 N,N-Dimethylaniline 22,676 ✔

0001582-09-8 Trifluralin 15,304 ✔ ✔

0000593-60-2 Vinyl bromide 2,620 ✔

0000082-68-8 Quintozene 2,558 ✔ ✔ ✔ ✔ ✔

0000062-73-7 Dichlorvos 1,286 ✔ ✔ ✔

0002164-17-2 Fluometuron 832 ✔

0000096-45-7 Ethylene thiourea 529 ✔

0012427-38-2 Maneb 272 ✔

0000542-88-1 Bis(chloromethyl) ether 255 ✔ ✔

0000091-94-1 3,3'-Dichlorobenzidine 10 ✔

0000114-26-1 Propoxur 4 ✔

0000070-30-4 Hexachlorophene ✔ ✔ ✔

0000133-07-3 Folpet ✔

0000126-72-7 Tris(2,3-dibromopropyl) phosphate ✔

0000122-34-9 Simazine ✔

0000121-82-4 Cyclotrimethylene trinitramine ✔ ✔

0000140-57-8 Aramite ✔ ✔

0000141-66-2 Dicrotophos ✔

0000143-50-0 Kepone ✔ ✔ ✔ ✔ ✔

0000131-89-5 2-Cyclohexyl-4,6-dinitrophenol ✔

0000576-26-1 2,6-Dimethylphenol ✔

0000709-98-8 Propanil ✔

0000621-64-7 N-Nitrosodi-n-propylamine ✔ ✔ ✔

0000616-23-9 2,3 Dichloropropanol ✔

0000615-54-3 1,2,4 Tribromobenzene ✔

0000330-55-2 Linuron ✔

0000598-77-6 1,1,2 Trichloropropane ✔

0000150-50-5 Merphos ✔

0000563-68-8 Thallium(I) acetate ✔

0000563-12-2 Ethion ✔

0000532-27-4 2-Chloroacetophenone ✔

0000510-15-6 Chlorobenzilate ✔

0000505-29-3 1,4 Dithiane ✔

0000330-54-1 Diuron ✔

0000300-76-5 Naled ✔

0000608-73-1 Hexachlorocyclohexane ✔ ✔

0000078-00-2 Tetraethyl lead ✔

0000088-85-7 Dinitrobutyl phenol ✔ ✔

4-7.XLS
EXHIBIT 4-7 (CONTINUED)

SCREENING OF HIGH-TOXICITY, PERSISTENT, BIOACCUMULATIVE/BIOCONCENTRATING

POSSIBLE NON-HAZARDOUS WASTE CONSTITUENTS AGAINST TRI RELEASE VOLUMES

Chemical CAS Chemical Name

Release 

Volume

Oral CSF

Inhalation Unit Risk

Oral RfD < 50th

RfC < 50th

AWQC (Chronic) < 50th

Degradation Rate for Water Column

Fish BCF

Henry's Law Constant

Kow

Soil Degradation Rate

Vapor Pressure > 1_3e-3

Beef Biotransfer Factor >7_8e-4

0000108-45-2 1,3-Phenylenediamine ✔

0000086-50-0 Azinphos-methyl ✔

0000085-00-7 Diquat ✔

0000083-79-4 Rotenone, Commercial ✔

0000121-75-5 Malathion ✔

0000078-48-8 S,S,S-Tributyltrithiophosphate ✔

0000093-65-2 Mecoprop ✔

0000075-87-6 Acetaldehyde, trichloro- ✔

0000062-74-8 Sodium fluoroacetate ✔

0000062-38-4 Phenylmercuric acetate ✔

0000057-24-9 Strychnine ✔

0000056-53-1 Diethylstilbestrol ✔ ✔ ✔

0000056-49-5 3-Methylcholanthrene ✔ ✔ ✔ ✔ ✔

0000056-35-9 Bis(tributyltin) oxide ✔

0000081-81-2 Warfarin ✔

0000101-61-1 4,4'-Methylenebis(N,N-dimethyl)benzenamine ✔

0000121-44-8 Triethylamine ✔

0000118-96-7 2,4,6-Trinitrotoluene ✔ ✔

0000765-34-4 Glycidylaldehyde ✔

0000107-19-7 Propargyl alcohol ✔

0000924-16-3 N-Nitrosodi-n-butylamine ✔ ✔ ✔

0000087-82-1 Hexabromobenzene ✔

0000103-33-3 Azobenzene ✔ ✔

0000093-76-5 2,4,5-T acid ✔

0000099-35-4 1,3,5-Trinitrobenzene ✔

0000097-63-2 Ethyl methacrylate ✔ ✔

0000095-65-8 3,4 Dimethylphenol ✔

0000095-57-8 2-Chlorophenol ✔ ✔ ✔

0000094-82-6 2,4-DB ✔

0000094-74-6 Methoxone ✔

0000094-59-7 Safrole ✔

0000106-37-6 1,4 Dibromobenzene ✔

0022967-92-6 Methyl mercury ✔

0033089-61-1 Amitraz ✔

0000822-06-0 Hexamethylene-1,6-diisocyanate ✔

0032534-81-9 Pentabromodiphenyl ether ✔

0030560-19-1 Acephate ✔ ✔

0029232-93-7 Pirimiphos methyl ✔

0028249-77-6 Thiobencarb ✔

0012035-72-2 Nickel subsulfide ✔

0025057-89-0 Bentazon ✔

0035554-44-0 Imazalil ✔

0022224-92-6 Fenamiphos ✔

0020859-73-8 Aluminum phosphide ✔

0019666-30-9 Oxydiazon ✔

0019408-74-3 Hexachlorodibenzo p dioxin, mixture (HxCDD) ✔ ✔

0015972-60-8 Alachlor ✔

0013593-03-8 Quinalphos ✔

0000834-12-8 Ametryn ✔

0026628-22-8 Sodium azide (Na(N3)) ✔

4-7.XLS
EXHIBIT 4-7 (CONTINUED)

SCREENING OF HIGH-TOXICITY, PERSISTENT, BIOACCUMULATIVE/BIOCONCENTRATING

POSSIBLE NON-HAZARDOUS WASTE CONSTITUENTS AGAINST TRI RELEASE VOLUMES

Chemical CAS Chemical Name

Release 

Volume

Oral CSF

Inhalation Unit Risk

Oral RfD < 50th

RfC < 50th

AWQC (Chronic) < 50th

Degradation Rate for Water Column

Fish BCF

Henry's Law Constant

Kow

Soil Degradation Rate

Vapor Pressure > 1_3e-3

Beef Biotransfer Factor >7_8e-4

0067747-09-5 Prochloraz ✔ ✔

0085509-19-9 NuStar ✔

0077501-63-4 Lactofen ✔

0077182-82-2 Glufosinate ammonium ✔

0076578-14-8 Quizalofop-ethyl ✔

0072178-02-0 Fomesafen ✔

0069806-40-2 Haloxyfop methyl ✔

0032536-52-0 Octabromodiphenyl ether ✔

0068085-85-8 Cyhalothrin ✔

0039638-32-9 Bis(2-chloroisopropyl) ether ✔

0067485-29-4 Hydramethylnon ✔

0065195-55-3 Avermectin B1 ✔

0062476-59-9 Acifluorfen, sodium salt ✔

0060568-05-0 Furmecyclox ✔

0060207-90-1 Propiconazole ✔

0055285-14-8 Carbosulfan ✔

0042874-03-3 Oxyfluorfen ✔

0069409-94-5 Fluvalinate ✔

0001314-84-7 Zinc phosphide ✔

0002385-85-5 Mirex ✔ ✔

0002303-16-4 Diallate ✔

0002104-64-5 EPN ✔

0001929-77-7 Carbamothioic acid, dipropyl-, S-propyl ester ✔

0001918-16-7 Propachlor ✔

0001646-88-4 Aldicarb sulfone ✔

0002425-06-1 Captafol ✔

0001309-64-4 Antimony trioxide ✔

0001116-54-7 N-Nitrosodiethanolamine ✔

0000950-37-8 Methidathion ✔

0000944-22-9 Fonofos ✔

0000930-55-2 N-Nitrosopyrrolidine ✔ ✔

0101200-48-0 Tribenuron methyl ✔

0000886-50-0 Terbutryn ✔

0000055-18-5 N-Nitrosodiethylamine ✔ ✔ ✔

0001910-42-5 Paraquat dichloride ✔

0007791-12-0 Thallium chloride TlCl ✔

0010595-95-6 N-Nitrosomethylethylamine ✔ ✔

0010265-92-6 Methamidophos ✔

0010102-45-1 Thallium(I) nitrate ✔

0002303-17-5 Triallate ✔

0008065-48-3 Demeton ✔ ✔

0002439-10-3 Dodine ✔

0007784-42-1 Arsine ✔

0007783-00-8 Selenious acid ✔

0007487-94-7 Mercuric chloride ✔

0007446-18-6 Thallium(I) sulfate ✔

0007287-19-6 Prometryn ✔

0006533-73-9 Thallium(I) carbonate ✔

0005902-51-2 Terbacil ✔

0002921-88-2 Chlorpyrifos ✔ ✔

0010061-01-5 cis-1,3-Dichloropropene ✔ ✔

4-7.XLS
EXHIBIT 4-8 POSSIBLE NON-HAZARDOUS INDUSTRIAL WASTE CONSTITUENTS BY CHEMICAL CLASS

Metals / Inorganics Volatile Chlorinated 

Organics

Volatile 

Hydrocarbons Other Volatile Organics Pesticides/Intermediates/Degradation Products Phenolic Compounds Polycyclic Aromatic Hydrocarbons Other Semivolatile Organics

Antimony trioxide 1,1,2 Trichloropropane 1,3-Butadiene 1,4 Dithiane 2,4,5-T acid Imazalil 2,6-Dimethylphenol 3-Methylcholanthrene 1,2,4 Tribromobenzene

Arsine 2,3 Dichloropropanol Azobenzene 2,4-DB Kepone 2-Chlorophenol 1,3,5-Trinitrobenzene

Chlorine dioxide Acetaldehyde, trichloro- Glycol Ethers Acephate Lactofen 2-Cyclohexyl-4,6-dinitrophenol 1,3-Phenylenediamine

Copper Bis(2-chloroisopropyl) ether Methyl mercury Acifluorfen, sodium salt Linuron 3,4 Dimethylphenol 1,4 Dibromobenzene

Cyanide Chloroprene N-Nitrosodi-n-butylamine Alachlor Malathion Dinitrobutyl phenol 2,4,6-Trinitrotoluene

Manganese cis-1,3-Dichloropropene N-Nitrosodi-n-propylamine Aldicarb sulfone Mecoprop 2-Chloroacetophenone

Mercuric chloride Freon 113 N-Nitrosodiethanolamine Aluminum phosphide Merphos 4,4'-Methylenebis(N,N-dimethyl)benzenamine

Nickel subsulfide N-Nitrosodiethylamine Ametryn Methamidophos Avermectin B1

Selenious acid N-Nitrosomethylethylamine Amitraz Methidathion Cyclotrimethylene trinitramine

Sodium azide (Na(N3)) Propargyl alcohol Aramite Methoxone Diethylstilbestrol

Thallium(I) chloride Propylene oxide Azinphos-methyl Mirex Ethyl methacrylate

Thallium(I) acetate Tetraethyl lead Bentazon N-Nitrosopyrrolidine Glycidylaldehyde

Thallium(I) carbonate Triethylamine Bis(tributyltin) oxide Naled Hexabromobenzene

Thallium(I) nitrate Captafol NuStar Hexachlorodibenzo p dioxin, mixture

Thallium(I) sulfate Carbamothioic acid, dipropyl-, S-propyl ester Oxydiazon Hexamethylene-1,6-diisocyanate

Zinc Carbosulfan Oxyfluorfen Octabromodiphenyl ether

Chlorobenzilate Paraquat dichloride Pentabromodiphenyl ether

Chlorpyrifos Phenylmercuric acetate Propiconazole

Cyhalothrin Pirimiphos methyl Safrole

Demeton Prochloraz Tris(2,3-dibromopropyl) phosphate

Diallate Prometryn

Dicrotophos Propachlor

Diquat Propanil

Diuron Quinalphos

Dodine Quizalofop-ethyl

EPN Rotenone, Commercial

Ethion S,S,S-Tributyltrithiophosphate

Fenamiphos Simazine

Fluvalinate Sodium fluoroacetate

Folpet Strychnine

Fomesafen Terbacil

Fonofos Terbutryn

Furmecyclox Thiobencarb

Glufosinate ammonium Triallate

Haloxyfop methyl Tribenuron methyl

Hexachlorocyclohexane Warfarin

Hexachlorophene Zinc phosphide

Hydramethylnon

12 17 1 13 75 5 1 20

Notes:

1. All thallium salts are counted as one entry.

4-8.XLS
EXHIBIT 4-9 SCREENING OF KNOWN NON-HAZARDOUS WASTE CONSTITUENTS AGAINST TRI RELEASE VOLUMES

Chemical CAS Chemical Name

Release 

Volume

Oral CSF

Inhalation Unit Risk

Oral RfD < 50th

RfC < 50th

Beef Biotransfer Factor >7_8e-4

AWQC (Chronic) < 50th

Degradation Rate for Water Column

Fish BAF

Fish BCF

Henry's Law Constant

Kow

Soil Degradation Rate

Vapor Pressure > 1_3e-3

0000067-56-1 Methanol 255,766,934 ✔ ✔

0000108-88-3 Toluene 168,958,681 ✔ ✔

0001330-20-7 Xylene (mixed isomers) 108,936,037 ✔ ✔

0000075-15-0 Carbon disulfide 83,384,729 ✔ ✔

 ---- Zinc compounds 81,764,720 ✔ ✔

0000075-09-2 Dichloromethane 63,774,566 ✔ ✔ ✔ ✔

 ---- Glycol Ethers 48,991,927

 ---- Copper compounds 47,115,338 ✔ ✔ ✔

 ---- Manganese compounds 41,504,786 ✔ ✔

0000100-42-5 Styrene 40,156,848 ✔ ✔

0000071-55-6 1,1,1-Trichloroethane 38,056,891 ✔ ✔

0000071-36-3 n-Butyl alcohol 30,081,146 ✔

0000108-10-1 Methyl isobutyl ketone 25,501,571 ✔ ✔

0000050-00-0 Formaldehyde 19,755,899 ✔ ✔ ✔

0000075-05-8 Acetonitrile 18,264,054 ✔ ✔ ✔

0000075-07-0 Acetaldehyde 13,052,168 ✔ ✔

0000100-41-4 Ethylbenzene 12,802,139 ✔ ✔

0000064-18-6 Formic acid 11,267,572 ✔

0007440-66-6 Zinc 10,155,449 ✔ ✔

0007439-96-5 Manganese 9,354,553 ✔

0000079-10-7 Acrylic acid 6,915,166 ✔

0000107-13-1 Acrylonitrile 6,379,861 ✔ ✔ ✔ ✔ ✔

0000079-06-1 Acrylamide 5,217,625 ✔ ✔ ✔

0000074-87-3 Chloromethane 5,174,937 ✔ ✔

0000075-71-8 Dichlorodifluoromethane 4,872,594 ✔ ✔

 ---- Cyanide compounds 4,382,509 ✔

0000091-20-3 Naphthalene 3,230,142 ✔

0000074-90-8 Hydrogen cyanide 3,143,253 ✔

0000075-69-4 Trichlorofluoromethane 2,994,474 ✔ ✔

0000074-83-9 Bromomethane 2,669,788 ✔ ✔ ✔ ✔

0000080-62-6 Methyl methacrylate 2,583,587 ✔ ✔

0007440-50-8 Copper 2,204,032 ✔ ✔ ✔

0000098-82-8 Cumene 2,057,269 ✔ ✔

0000062-53-3 Aniline 1,976,326 ✔ ✔

 ---- Nickel compounds 1,665,815 ✔ ✔ ✔

 ---- Antimony compounds 1,445,522 ✔ ✔ ✔ ✔

4-9.XLS
EXHIBIT 4-9 (CONTINUED)

SCREENING OF KNOWN NON-HAZARDOUS WASTE CONSTITUENTS AGAINST TRI RELEASE VOLUMES

Chemical CAS Chemical Name

Release 

Volume

Oral CSF

Inhalation Unit Risk

Oral RfD < 50th

RfC < 50th

Beef Biotransfer Factor >7_8e-4

AWQC (Chronic) < 50th

Degradation Rate for Water Column

Fish BAF

Fish BCF

Henry's Law Constant

Kow

Soil Degradation Rate

Vapor Pressure > 1_3e-3

0000107-02-8 Acrolein 170,087 ✔ ✔ ✔

0007440-36-0 Antimony 128,663 ✔ ✔ ✔ ✔

0000099-65-0 m-Dinitrobenzene 100,719 ✔

0000074-95-3 Methylene bromide 77,545 ✔ ✔

0007723-14-0 Phosphorus 50,768 ✔

0007440-62-2 Vanadium (fume or dust) 41,023 ✔ ✔ ✔

0000079-46-9 2-Nitropropane 40,523 ✔ ✔

0000051-28-5 2,4-Dinitrophenol 39,344 ✔

0000542-75-6 1,3-Dichloropropylene 24,756 ✔ ✔ ✔

0007440-41-7 Beryllium 23,795 ✔ ✔ ✔ ✔ ✔ ✔

0000075-34-3 Ethylidene Dichloride 23,492 ✔ ✔

0000100-44-7 Benzyl chloride 23,331 ✔ ✔ ✔

0000106-93-4 1,2-Dibromoethane 18,537 ✔ ✔ ✔ ✔

0000302-01-2 Hydrazine 16,956 ✔ ✔

0000120-83-2 2,4-Dichlorophenol 14,760 ✔

0000079-34-5 1,1,2,2-Tetrachloroethane 14,027 ✔ ✔ ✔ ✔

0000630-20-6 1,1,1,2-Tetrachloroethane 11,746 ✔ ✔ ✔ ✔

0000077-47-4 Hexachlorocyclopentadiene 9,174 ✔ ✔ ✔ ✔ ✔ ✔

0000111-44-4 Bis(2-chloroethyl) ether 3,237 ✔ ✔ ✔ ✔

0000137-26-8 Thiram 3,184 ✔

0000098-07-7 Benzoic trichloride 2,868 ✔

0000056-38-2 Parathion 1,147 ✔

0007440-28-0 Thallium 1,010 ✔ ✔ ✔

0000075-27-4 Dichlorobromomethane 0 ✔ ✔ ✔

0000086-30-6 N-Nitrosodiphenylamine 0 ✔ ✔

0001336-36-3 Polychlorinated biphenyls 0 ✔ ✔ ✔ ✔ ✔

0000096-18-4 1,2,3-Trichloropropane ✔ ✔ ✔

0000095-94-3 1,2,4,5-Tetrachlorobenzene ✔ ✔ ✔ ✔

0000096-12-8 1,2-Dibromo-3-chloropropane ✔ ✔

0000156-60-5 1,2-Dichloroethylene, trans ✔ ✔

0000122-66-7 1,2-Diphenylhydrazine ✔ ✔

0000058-90-2 2,3,4,6-Tetrachlorophenol ✔ ✔

0001746-01-6 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) ✔ ✔ ✔ ✔ ✔ ✔

0000057-97-6 7,12-Dimethylbenz[a]anthracene ✔ ✔

0000083-32-9 Acenaphthene ✔

0000067-64-1 Acetone ✔ ✔

0000116-06-3 Aldicarb ✔

0000309-00-2 Aldrin ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔

0000959-98-8 alpha - Endosulfan ✔

0000319-84-6 alpha-Hexachlorocyclohexane ✔ ✔ ✔

0000056-55-3 Benz[a]anthracene ✔ ✔ ✔ ✔

0000218-01-9 Benzo(a)phenanthrene ✔ ✔ ✔ ✔

0000050-32-8 Benzo[a]pyrene ✔ ✔ ✔ ✔ ✔

0000205-99-2 Benzo[b]fluoranthene ✔ ✔ ✔ ✔ ✔

0033213-65-9 beta - Endosulfan ✔

4-9.XLS
EXHIBIT 4-9 (CONTINUED)

SCREENING OF KNOWN NON-HAZARDOUS WASTE CONSTITUENTS AGAINST TRI RELEASE VOLUMES

Chemical CAS Chemical Name

Release 

Volume

Oral CSF

Inhalation Unit Risk

Oral RfD < 50th

RfC < 50th

Beef Biotransfer Factor >7_8e-4

AWQC (Chronic) < 50th

Degradation Rate for Water Column

Fish BAF

Fish BCF

Henry's Law Constant

Kow

Soil Degradation Rate

Vapor Pressure > 1_3e-3

0000319-85-7 beta-BHC ✔ ✔ ✔

0000075-25-2 Bromoform ✔ ✔ ✔ ✔

0000085-68-7 Butyl benzyl phthalate ✔ ✔

0001563-66-2 Carbofuran ✔

0000124-48-1 Chlorodibromomethane ✔ ✔ ✔

0018540-29-9 Chromium(VI) ✔ ✔

0000156-59-2 cis-1,2-Dichloroethylene ✔ ✔

0008007-45-2 Coal tars ✔

0000544-92-3 Copper cyanide ✔

0000057-12-5 Cyanides (soluble salts and complexes) ✔

0000072-54-8 DDD ✔ ✔ ✔ ✔ ✔ ✔

0000072-55-9 DDE ✔ ✔ ✔ ✔ ✔ ✔ ✔

0000050-29-3 DDT ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔

0000053-70-3 Dibenz[a,h]anthracene ✔ ✔ ✔ ✔

0000060-57-1 Dieldrin ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔

0000060-51-5 Dimethoate ✔

0000298-04-4 Disulfoton ✔

0000115-29-7 Endosulfan ✔ ✔ ✔

0000060-29-7 Ethane, 1,1'-oxybis- ✔ ✔

0000141-78-6 Ethyl acetate ✔ ✔

0000206-44-0 Fluoranthene ✔ ✔

0000086-73-7 Fluorene ✔

0000110-00-9 Furan ✔ ✔ ✔

0000098-01-1 Furfural ✔

0007783-06-4 Hydrogen sulfide ✔ ✔ ✔

0000193-39-5 Indeno(1,2,3-cd)pyrene ✔ ✔ ✔ ✔

0000078-83-1 Isobutyl alcohol ✔ ✔

0000078-59-1 Isophorone ✔

0000298-00-0 Methyl parathion ✔

0002212-67-1 Molinate ✔

0007439-98-7 Molybdenum ✔ ✔ ✔ ✔

0000117-84-0 n-Dioctylphthalate ✔ ✔ ✔

0000062-75-9 N-Nitrosodimethylamine ✔ ✔ ✔

0000106-47-8 p-Chloroaniline ✔ ✔ ✔

0000608-93-5 Pentachlorobenzene ✔ ✔ ✔ ✔ ✔

0000298-02-2 Phorate ✔

0007803-51-2 Phosphine ✔ ✔

0000129-00-0 Pyrene ✔ ✔ ✔ ✔

0003689-24-5 Sulfotep ✔

0010061-02-6 trans-1,3-Dichloropropene ✔ ✔

0001314-62-1 Vanadium pentoxide ✔

4-9.XLS
EXHIBIT 4-10 TOXICITY SUMMARY OF KNOWN AND POSSIBLE NON-HAZARDOUS INDUSTRIAL WASTE CONSTITUENTS

Inhalation Unit Risk (All) Inhalation Unit Risk > 

50th Percentile Oral CSF (All) Oral CSF > 50th Percentile Oral RfD < 50th Percentile Oral RfD < 50th Percentile (Continued)

AWQC (Chronic Freshwater) < 

50th Percentile

1,1,1,2-Tetrachloroethane Acrylamide 1,1,1,2-Tetrachloroethane 1,2-Dibromoethane 1,1,2 Trichloropropane Glycidylaldehyde 2,3,7,8-TCDD

1,1,2,2-Tetrachloroethane Aldrin 1,1,2,2-Tetrachloroethane 1,2-Diphenylhydrazine 1,1,2-Trichloroethane Haloxyfop methyl alpha - Endosulfan

1,1,2-Trichloroethane alpha-Hexachlorocyclohexane 1,1,2-Trichloroethane 2,3,7,8-TCDD 1,2,3-Trichloropropane Hexabromobenzene Antimony

1,2-Dibromoethane Benzidine 1,2-Dibromoethane Acrylamide 1,2,4 Tribromobenzene Hexachlorocyclopentadiene Azinphos-methyl

1,2-Diphenylhydrazine Beryllium 1,2-Diphenylhydrazine Acrylonitrile 1,2,4,5-Tetrachlorobenzene Hexachloroethane beta - Endosulfan

1,3-Butadiene beta-BHC 1,4-Dioxane Aldrin 1,2,4-Trichlorobenzene Hydramethylnon Chlorpyrifos

Acetaldehyde Bis(2-chloroethyl) ether 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) alpha-Hexachlorocyclohexane 1,3,5-Trinitrobenzene Hydrogen sulfide Copper

Acrylamide Coal tars 2,4,6-Trinitrotoluene Benzo[a]pyrene 1,3-Dichloropropylene Imazalil Cyanides (soluble salts and complexes)

Acrylonitrile Dieldrin 4,4'-Methylenebis(N,N-dimethyl)benzenamine Benzoic trichloride 1,3-Phenylenediamine Lactofen DDT

Aldrin Hexachlorocyclohexane Acephate Beryllium 1,4 Dibromobenzene Linuron Demeton

alpha-Hexachlorocyclohexane HxCDD, mixture Acrylamide beta-BHC 1,4 Dithiane m-Dinitrobenzene Dieldrin

Aramite Hydrazine Acrylonitrile Bis(2-chloroethyl) ether 2,3 Dichloropropanol Mecoprop Endosulfan

Azobenzene N-Nitrosodi-n-butylamine Aldrin DDE 2,4,5-T acid Mercuric chloride Hexachlorocyclopentadiene

Beryllium N-Nitrosodiethylamine alpha-Hexachlorocyclohexane DDT 2,4,6-Trinitrotoluene Merphos Hydrogen sulfide

beta-BHC N-Nitrosodimethylamine Aniline Dieldrin 2,4-DB Methamidophos Malathion

Bis(2-chloroethyl) ether N-Nitrosopyrrolidine Aramite Hexachlorocyclohexane 2,4-Dichlorophenol Methidathion Mirex

Bis(chloromethyl) ether Nickel subsulfide Azobenzene HxCDD, mixture 2,4-Dinitrophenol Methoxone Parathion

Bromoform Benzo[a]pyrene Hydrazine 2,6-Dimethylphenol Methyl mercury Polychlorinated biphenyls

Coal tars Benzoic trichloride N-Nitrosodi-n-butylamine 2-Chlorophenol Methyl parathion

DDT Benzyl chloride N-Nitrosodi-n-propylamine 2-Cyclohexyl-4,6-dinitrophenol Mirex

Dichloromethane Beryllium N-Nitrosodiethanolamine 3,4 Dimethylphenol Molinate

Dieldrin beta-BHC N-Nitrosodiethylamine Acephate Molybdenum

Epichlorohydrin Bis(2-chloroethyl) ether N-Nitrosodimethylamine Acetaldehyde, trichloro- Naled

Formaldehyde Bromoform N-Nitrosomethylethylamine Acetonitrile NuStar

Hexachlorocyclohexane Chlorodibromomethane N-Nitrosopyrrolidine Acifluorfen, sodium salt Octabromodiphenyl ether

Hexachlorodibenzo p dioxin, mixture (HxCDD) Cyclotrimethylene trinitramine Polychlorinated biphenyls Acrylamide Oxydiazon

Hydrazine DDD Vinylidene chloride Alachlor Oxyfluorfen

Nickel compounds DDE Aldicarb p-Chloroaniline

N-Nitrosodi-n-butylamine DDT Aldicarb sulfone Paraquat dichloride

N-Nitrosodiethylamine Di(2-ethylhexyl) phthalate Aldrin Pentabromodiphenyl ether

N-Nitrosodimethylamine Dichlorobromomethane Allyl alcohol Pentachlorobenzene

N-Nitrosopyrrolidine Dichloromethane Aluminum phosphide Phenylmercuric acetate

Nickel subsulfide Dieldrin Ametryn Phosphine

Propylene oxide Epichlorohydrin Amitraz Phosphorus

Vinylidene chloride Folpet Antimony Pirimiphos methyl

Fomesafen Avermectin B1 Prochloraz

Furmecyclox Bentazon Prometryn

Hexachlorocyclohexane Beryllium Propachlor

Hexachlorodibenzo p dioxin, mixture (HxCDD) Bis(tributyltin) oxide Propanil

Hydrazine Bromomethane Propargyl alcohol

Isophorone Captafol Propiconazole

N-Nitrosodi-n-butylamine Carbamothioic acid, dipropyl-, S-propyl ester Quinalphos

N-Nitrosodi-n-propylamine Carbofuran Quizalofop-ethyl

N-Nitrosodiethanolamine Carbosulfan Rotenone, Commercial

N-Nitrosodiethylamine Chlorpyrifos S,S,S-Tributyltrithiophosphate

N-Nitrosodimethylamine Copper cyanide Selenious acid

N-Nitrosodiphenylamine Cyclotrimethylene trinitramine Simazine

N-Nitrosomethylethylamine Cyhalothrin Sodium azide (Na(N3))

N-Nitrosopyrrolidine DDT Sodium fluoroacetate

Polychlorinated biphenyls Demeton Strychnine

Prochloraz Dicrotophos Sulfotep

Propylene oxide Dieldrin Terbacil

Vinylidene chloride Dimethoate Terbutryn

Dinitrobutyl phenol Tetraethyl lead

Diquat Thallium chloride TlCl

Disulfoton Thallium(I) acetate

Diuron Thallium(I) carbonate

Dodine Thallium(I) nitrate

Endosulfan Thallium(I) sulfate

EPN Thiobencarb

Ethion Thiram

Fenamiphos Triallate

Fluvalinate Tribenuron methyl

Fonofos Vanadium pentoxide

Furan Vinylidene chloride

Furfural Warfarin

Glufosinate ammonium Zinc phosphide

4-10.XLS
EXHIBIT 4-12 TRI RELEASES AND NON-CONFIDENTIAL TSCA PRODUCTION VOLUME DATA FOR

THE KNOWN AND POSSIBLE NON-HAZARDOUS INDUSTRIAL WASTE CONSTITUENTS

Chemical CAS Chemical Name

1994 TRI Release 

Volume > 1 million lbs.

1994 Non-Confidential TSCA 

Production Volume > 1 million lbs.

Known Chemicals

0000071-55-6 1,1,1-Trichloroethane X

0000079-00-5 1,1,2-Trichloroethane X

0000095-63-6 1,2,4-Trimethylbenzene X

0000107-06-2 1,2-Dichloroethane X

0000542-75-6 1,3-Dichloropropylene X

0000075-07-0 Acetaldehyde X

0000075-05-8 Acetonitrile X X

0000079-06-1 Acrylamide X X

0000079-10-7 Acrylic acid X

0000107-13-1 Acrylonitrile X

0007429-90-5 Aluminum (fume or dust) X

0007664-41-7 Ammonia X

0000062-53-3 Aniline X

 ---- Antimony compounds X

0000071-43-2 Benzene X

0000074-83-9 Bromomethane X CBI

0000075-15-0 Carbon disulfide X

0000056-23-5 Carbon tetrachloride X

0007782-50-5 Chlorine X

0000108-90-7 Chlorobenzene X

0000075-00-3 Chloroethane X

0000067-66-3 Chloroform X X

0000074-87-3 Chloromethane X

0007440-47-3 Chromium X

0007440-50-8 Copper X

0008001-58-9 Creosote X

0001319-77-3 Cresol (mixed isomers) X

0000098-82-8 Cumene X

 ---- Cyanide compounds X

0000075-71-8 Dichlorodifluoromethane X

0000075-09-2 Dichloromethane X

0000100-41-4 Ethylbenzene X

0000107-21-1 Ethylene glycol X

0000050-00-0 Formaldehyde X

0000064-18-6 Formic acid X

 ---- Glycol Ethers X

0000067-72-1 Hexachloroethane X

0000074-90-8 Hydrogen cyanide X

0007664-39-3 Hydrogen fluoride X

0007783-06-4 Hydrogen sulfide X

0007439-96-5 Manganese X

0000067-56-1 Methanol X

0000078-93-3 Methyl ethyl ketone X

0000108-10-1 Methyl isobutyl ketone X

0000080-62-6 Methyl methacrylate X

0000071-36-3 n-Butyl alcohol X

0000091-20-3 Naphthalene X

 ---- Nickel compounds X

0000095-47-6 o-Xylene X

0000106-42-3 p-Xylene X

0000108-95-2 Phenol X

0000100-42-5 Styrene X

0000127-18-4 Tetrachloroethylene X X

0000108-88-3 Toluene X

0000079-01-6 Trichloroethylene X

0000075-69-4 Trichlorofluoromethane X

0000108-05-4 Vinyl acetate X

0000075-01-4 Vinyl chloride X X

0001330-20-7 Xylene (mixed isomers) X

0007440-66-6 Zinc X

Possible Chemicals

0000106-99-0 1,3-Butadiene X

0000576-26-1 2,6-Dimethylphenol X

0001332-21-4 Asbestos (friable) X

0010049-04-4 Chlorine dioxide X

0000126-99-8 Chloroprene X

0000121-82-4 Cyclotrimethylene trinitramine X

0000076-13-1 Freon 113 X

0000121-69-7 N,N-Dimethylaniline X

0000075-56-9 Propylene oxide X
EXHIBIT 4-13 VOLATILITY, PERSISTENCE, AND BIOACCUMULATION/BIOCONCENTRATION SUMMARY POTENTIAL OF KNOWN AND POSSIBLE NON-HAZARDOUS INDUSTRIAL WASTE CONSTITUENTS

Vapor Pressure > 

1.3e-3 atm.

Air Half-Life > 

75th Percentile

Low Soil/Water Degradation 

Constant (< 0.5) Kow >105 High Fish BAF (>1000) High Fish BCF (>1000)

1,1,1,2-Tetrachloroethane Dichloromethane 1,2-Dichloropropane 2,3,7,8-TCDD 1,2,4,5-Tetrachlorobenzene 2,3,4,6-Tetrachlorophenol

1,1,1-Trichloroethane Polychlorinated biphenyls 2,3,7,8-TCDD 3-Methylcholanthrene alpha-Hexachlorocyclohexane 3-Methylcholanthrene

1,1,2,2-Tetrachloroethane 3-Methylcholanthrene 7,12-Dimethylbenz[a]anthracene beta-BHC Aldrin

1,1,2-Trichloroethane Aldrin Aldrin DDE Butyl benzyl phthalate

1,2,3-Trichloropropane Antimony Benz[a]anthracene DDT Chlorobenzilate

1,2-Dibromoethane Benz[a]anthracene Benzo(a)phenanthrene DDD

1,2-Dichlorobenzene Benzo(a)phenanthrene Benzo[a]pyrene Diallate

1,2-Dichloroethylene, trans Benzo[a]pyrene Benzo[b]fluoranthene Dibutyl phthalate

1,2-Dichloropropane Benzo[b]fluoranthene DDD Dieldrin

1,3-Dichloropropylene Beryllium DDE Diethylstilbestrol

1,4-Dioxane Copper DDT Hexachlorocyclopentadiene

2-Chlorophenol DDD Di(2-ethylhexyl) phthalate Kepone

2-Ethoxyethanol DDE Dibenz[a,h]anthracene Pentachlorobenzene

2-Nitropropane DDT Dieldrin

Acetone Dibenz[a,h]anthracene Diethylstilbestrol

Acetonitrile Dieldrin Fluoranthene

Acrolein Indeno(1,2,3-cd)pyrene Hexachlorocyclopentadiene

Acrylonitrile Kepone Indeno(1,2,3-cd)pyrene

Allyl chloride Manganese Kepone

Benzyl chloride Molybdenum n-Dioctylphthalate

Bis(2-chloroethyl) ether Nickel Pentachlorobenzene

Bromoform Pyrene Polychlorinated biphenyls

Bromomethane Thallium Pyrene

Carbon disulfide Vanadium (fume or dust)

Chlorodibromomethane Zinc

Chloromethane

Chloroprene

cis-1,2-Dichloroethylene

cis-1,3-Dichloropropene

Cumene

Dichlorobromomethane

Dichlorodifluoromethane

Dichloromethane

Epichlorohydrin

Ethane, 1,1'-oxybisEthyl acetate

Ethyl methacrylate

Ethylbenzene

Ethylidene Dichloride

Formaldehyde

Formic acid

Freon 113

Furan

Isobutyl alcohol

Methanol

Methyl isobutyl ketone

Methyl methacrylate

Methylene bromide

n-Butyl alcohol

N-Nitrosodi-n-propylamine

N-Nitrosodiethylamine

N-Nitrosodimethylamine

N-Nitrosomethylethylamine

p-Chloroaniline

Styrene

Toluene

trans-1,3-Dichloropropene

Trichlorofluoromethane

Vinylidene chloride

Xylene (mixed isomers)

4-13.XLS
AZARDOUS INDUSTRIAL WASTE CONSTITUENTS

Beef Biotransfer Factor > 7.8e-4

1,2,4,5-Tetrachlorobenzene

2,3,7,8-TCDD

3-Methylcholanthrene

7,12-Dimethylbenz[a]anthracene

Aldrin

Antimony

Benz[a]anthracene

Benzo(a)phenanthrene

Benzo[a]pyrene

Benzo[b]fluoranthene

Beryllium

Butyl benzyl phthalate

Copper

DDD

DDE

DDT

Di(2-ethylhexyl) phthalate

Dibenz[a,h]anthracene

Dibutyl phthalate

Dieldrin

Diethylstilbestrol

Fluoranthene

Hexachlorocyclopentadiene

Indeno(1,2,3-cd)pyrene

Kepone

Molybdenum

n-Dioctylphthalate

Nickel

Pentachlorobenzene

Polychlorinated biphenyls

Pyrene

Thallium

Vanadium (fume or dust)

4-13.XLS
EXHIBIT 4-16 LOWEST PROPOSED EXIT LEVELS FOR CHEMICALS

Constituent

Lowest Exit Level for 

chemicals from HWIR 

waste models (mg/L) Model

1,1,1,2-Tetrachloroethane 0.0078 Groundwater

1,1,1-Trichloroethane 0.0539 Groundwater

1,1,2,2-Tetrachloroethane 0.0037 Direct inhalation

1,1,2-Trichloroethane 0.0018 Groundwater

1,2,3-Trichloropropane 0.34 Groundwater

1,2,4,5-Tetrachlorobenzene 0.0317 Groundwater

1,2,4-Trichlorobenzene 0.685 Direct inhalation

1,2-Dibromo-3-chloropropane 0.000114 Groundwater

1,2-Dichlorobenzene 6.1 Groundwater

1,2-Dichloropropane 0.0023 Groundwater

1,3,5-Trinitrobenzene 0.003 Groundwater

1,3-Dichloropropylene (1,3-Dichloropropene) 0.00085 Groundwater

1,3-Phenylenediamine 0.3 Groundwater

1,4-Dioxane 0.0136 Groundwater

2,3,4,6-Tetrachlorophenol 0.58 Groundwater

2,3,7,8-TCDD 1.78E-10 Groundwater

2,4,5-T acid 0.64 Groundwater

2,4-Dichlorophenol 0.18 Groundwater

2,4-Dimethylphenol 1.19 Groundwater

2,4-Dinitrophenol 0.105 Groundwater

2,6-Dinitrotoluene 0.064 Groundwater

2-Chlorophenol 0.32 Groundwater

2-Ethoxyethanol 14.7 Direct inhalation

2-Nitropropane 0.00019 Direct inhalation-worker

3,3'-Dimethoxybenzidine 0.0102 Groundwater

3-Methylcholanthrene 1.41E-06 Groundwater

7,12-Dimethylbenz[a]anthracene 2.76E-06 Groundwater

Acenaphthene 4.9 Groundwater

Acetone 6 Groundwater

Acetonitrile 0.3 Groundwater

Acetophenone 6.4 Groundwater

Acrolein 0.00248 Direct inhalation-worker

Acrylamide 0.000038 Groundwater

Acrylonitrile 0.00034 Groundwater

Aldrin 5.64E-07 Beef/milk ingestion

Allyl chloride 0.0742 Direct inhalation

alpha-Hexachlorocyclohexane 0.000142 Vegetable/root ingestion

Aniline 0.017 Groundwater

Antimony 0.053 Groundwater

Benz[a]anthracene 4.30E-06 Groundwater

Benzidine 6.80E-07 Groundwater

Benzo(a)pyrene 7.04E-06 Groundwater

Benzo[b]fluoranthene 0.0000661 Groundwater

Benzyl alcohol 15 Groundwater

Benzyl chloride 1.13 Vegetable/root ingestion

Beryllium 0.00032 Groundwater

4-16.txt
EXHIBIT 4-16 (CONTINUED - PAGE 2)

LOWEST PROPOSED EXIT LEVELS FOR CHEMICALS

Constituent

Lowest Exit Level for 

chemicals from HWIR 

waste models (mg/L) Model

beta-BHC 0.00021 Groundwater

Bis(2-chloroethyl) ether 0.00036 Groundwater

Bis(2-chloroisopropyl) ether 0.0019 Groundwater

Bromoform 0.018 Groundwater

Bromomethane (Methyl bromide) 0.37 Direct inhalation

Butyl benzyl phthalate 64 Groundwater

Carbon disulfide 0.738 Direct inhalation

Chlorobenzilate 0.0057 Groundwater

Chlorodibromomethane 0.0018 Groundwater

Chloromethane (Methyl chloride) 0.0959 Direct inhalation

Chloroprene (Chloro-1,3-butadiene, 2-) 0.515 Direct inhalation

cis-1,2-Dichloroethylene 0.64 Groundwater

cis-1,3-Dichloropropene 0.00485 Direct inhalation

Copper 5.91 Ecological (aquatic plants)

DDD 0.000126 Beef/milk ingestion

DDE 9.11E-06 Beef/milk ingestion

DDT 0.0000181 Beef/milk ingestion

Di(2-ethylhexyl) phthalate (BEHP) 0.00044 Beef/milk ingestion

Diallate 0.26 Vegetable/root ingestion

Dibenz[a,h]anthracene 6.34E-07 Groundwater

Dibutyl Phthalate (Di-n-butyl phthalate) 25.2 Groundwater

Dichlorodifluoromethane 11.9 Groundwater

Dieldrin 0.000059 Beef/milk ingestion

Diethyl Phthalate 54 Groundwater

Diethylstilbestrol 2.47E-11 Beef/milk ingestion

Dimethoate 0.77 Groundwater

Dimethyl Phthalate 3 Multimedia model

Diphenylamine 2.6 Groundwater

Disulfoton 0.0131 Groundwater

Endosulfan 0.94 Groundwater

Epichlorohydrin 0.335 Direct inhalation-worker

Ethyl acetate 114 Groundwater

Ethyl methacrylate 6.6 Groundwater

Ethylbenzene 8.1 Groundwater

Fluoranthene 1.74 Groundwater

Fluorene 3.4 Groundwater

Formaldehyde 0.0158 Direct inhalation-worker

Formic acid 105 Groundwater

Glycidylaldehyde 6.2 Groundwater

Hexachlorocyclopentadiene 0.00521 Direct inhalation

Hexachlorophene 5.15E-06 Beef/milk ingestion

Indeno(1,2,3-cd)pyrene 0.0000241 Groundwater

Isobutyl alcohol 15 Groundwater

Isophorone 0.162 Groundwater

Kepone 0.0000264 Beef/milk ingestion

4-16.txt
EXHIBIT 4-16 (CONTINUED - PAGE 3)

LOWEST PROPOSED EXIT LEVELS FOR CHEMICALS

Constituent

Lowest Exit Level for 

chemicals from HWIR 

waste models (mg/L) Model

m-Dinitrobenzene (1,3-Dinitrobenzene) 0.0064 Groundwater

Methanol 30 Groundwater

Methyl isobutyl ketone 3 Groundwater

Methyl methacrylate 8.1 Groundwater

Methyl parathion 0.662 Vegetable/root ingestion

Methylene bromide 0.19 Groundwater

Molybdenum 1.83 Groundwater

n-Dioctyl phthalate 0.002 Beef/milk ingestion

N-Nitroso-dimethyl amine 3.40E-06 Groundwater

N-Nitrosodi-n-butylamine 0.000036 Groundwater

N-Nitrosodi-n-propylamine 0.000017 Groundwater

N-Nitrosodiethylamine 3.18E-06 Groundwater

N-Nitrosodiphenyl amine 0.046 Groundwater

N-Nitrosomethylethylamine 6.80E-06 Groundwater

N-Nitrosopyrrolidine 0.000068 Groundwater

Naphthalene 2.7 Groundwater

Nickel 4.89 Groundwater

p-Chloroaniline 0.16 Groundwater

Parathion 0.128 Ecological (fish/aquatic organisms)

Pentachlorobenzene 0.0543 Groundwater

Phenol 32 Groundwater

Phenylmercuric acetate 0.0045 Groundwater

Phorate 0.106 Vegetable/root ingestion

Polychlorinated biphenyls 4.81E-06 Groundwater

Pyrene 1.69 Groundwater

Safrole 0.00095 Groundwater

Strychnine 0.0041 Vegetable/root ingestion

Styrene 15.4 Groundwater

Thallium 0.0192 Groundwater

Toluene 12.6 Groundwater

trans-1,2-Dichloroethylene 1.12 Groundwater

trans-1,3-Dichloropropene 0.0049 Direct inhalation

Trichlorofluoromethane 16 Groundwater

Tris(2,3-dibromopropyl) phosphate 0.000099 Groundwater

Vanadium (fume or dust) 3.71 Groundwater

Xylenes 22.4 Direct inhalation

Zinc 38.4 Groundwater

Notes:

Bolded chemicals have the lowest exit level in a non-groundwater pathway

4-16.txt
Page 5-1

CHAPTER 5. POTENTIAL GAPS ASSOCIATED WITH

NATURAL RESOURCE DAMAGES AND LARGE-SCALE

ENVIRONMENTAL PROBLEMS

This chapter discusses risks associated with non-hazardous industrial waste management that are not

addressed in Chapters 3 or 4. Chapter 3 examined potential gaps inherent in the current hazardous waste

characteristics, thereby focusing on the adverse effects that the characteristics were meant to address, namely

risks arising primarily from acute events such as fires, explosions, and acute exposures of waste management and

transportation workers, and health risks caused by local environmental contamination near waste management units. 

Chapter 4 examined potential gaps associated with adverse human health or localized ecological effects from

constituents not included in the toxicity characteristic. This chapter addresses a third set of risks associated

with non-hazardous industrial waste management.

Section 5.1 addresses the pollution of groundwater by constituents that diminish the

value and usability of the resource without threatening human health;

Section 5.2 addresses damage from non-hazardous industrial waste management to air

quality through odors that harm the quality of life but may not have severe health

effects; and

Section 5.3 examines possible contributions to regional and global environmental

problems from the management of non-hazardous industrial waste, including: air

deposition to the Great Waters, damages from airborne particulates, global climate

change, potential damage from endocrine disruptors, red tides, stratospheric ozone

depletion, tropospheric ozone and photochemical air pollution, and water pollution.

These environmental problems may or may not meet the RCRA statutory or regulatory definitions of the types of risks

that the hazardous waste management program is meant to address.

5.1 Damage to Groundwater Resources

As noted in Chapter 2, the most common and well-documented impact of releases from non-hazardous

industrial waste management is groundwater contamination. If contamination is present at high enough

concentrations, the use of the groundwater as a water supply for human consumption or other use may result in

adverse effects on health. Human health risks associated with exposure to toxic pollutants are not the only

concern associated with groundwater contamination, however. Non-toxic pollutants such as iron, chloride, or

total dissolved solids may be present in concentrations that damage the aesthetic qualities and usability of the

water without posing outright health hazards. In areas where groundwater is used as a drinking water supply, such

water pollution must be remediated, limitations must be placed on its use, and/or alternative sources must be

found. These actions may be expensive and strain existing water supplies. Where alternative supplies are not

economically available, groundwater resources of marginal quality, which do not exceed health-based levels, may

continue to be used. Even where the polluted groundwater is not used for drinking water, the value of the resource

may decline because it is no longer available for future use as drinking water without remediation.

This non-toxic pollution of groundwater from non-hazardous industrial waste management was found

relatively often in the environmental release descriptions summarized in Chapter 2. Seventy-five (84 percent) of
Page 5-2

the 89 release descriptions with data on regulatory levels had constituents detected at levels exceeding nonhealth-based or non-ecologically-based standards, principally on aesthetic or usability criteria developed under

the Safe Drinking Water Act as Secondary Maximum Contaminant Levels (SMCLs). Releases at 70 of these 75 sites also

exceeded health and/or ecological-based standards. Of the 177 non-TC constituents identified in the release case

studies, 9 constituents (plus pH and total dissolved solids) have SMCLs. (Some of these constituents also have

health-based or ecologically-based levels.) Exhibit 5-1 lists all constituents with SMCLs and shows how

frequently they were found among the 89 case studies where concentration and regulatory standards data were

available. The most commonly detected constituents, iron, chloride, and manganese, all have SMCLs. Also, all

SMCLs, except those for foaming agents, color, and corrosivity, were violated by at least several documented

releases. (See Exhibit 2-6 for additional data on the concentrations at which these constituents were detected.)

Exhibit 5-1

Constituents/Properties with SMCLs Found in Release Descriptions

Constituents/Properties Number of Times Detected Number of Times Detected

Above SMCL

pH 66 24

Iron 54 49

Chloride 52 32

Sulfate 50 29

Total dissolved solids 48 29

Manganese 39 34

Zinc 33 13

Copper 17 2

Aluminum 12 12

Fluorides 12 4

Color 0 0

Corrosivity 0 0

Odor 0 0

Foaming agents 0 0

5.2 Damage to Local Air Quality from Odors

Noxious odors historically have been reported in the vicinity of waste management facilities. Odor

problems have caused minor health problems, reduced the quality of life, and reduced property values near such

facilities. Information on the extent of such problems from non-hazardous industrial waste management is very

limited. Odor problems were reported in several of the release descriptions initially identified by EPA, but

these cases were excluded because they did not meet the Agency's strict selection criteria. Only one release

description included reports by residents of odor problems. Nevertheless, the case study development methodology
Page 5-3

may have missed many cases of odor problems from non-hazardous industrial waste management facilities because

state regulatory programs largely focus on groundwater concerns. Also, odor problems are often handled at the

local level and thus the states may not get involved.

The potential for odor problems clearly exists at non-hazardous industrial waste facilities that manage

certain types of wastes. For example, food processing facilities (e.g., slaughterhouses that must dispose of

offal and alimentary contents from slaughtered animals) may have odor problems if their air releases are not

carefully managed. In addition to food wastes, potential odor problems may arise from chemical wastes. Exhibit 5-

2 lists a number of the chemicals identified in the release descriptions (although not necessarily for odor) that

have extremely low odor thresholds in either air or water. Ten of these chemicals have threshold odor

concentrations in air (the lowest concentrations at which odors can be detected or recognized) of 0.01 mg/m or 3

less, and six of them can be detected by odor in water solutions at concentrations of 0.006 mg/l or less.

Exhibit 5-2

Chemicals from Release Descriptions with Low Odor Thresholds

Chemical Name Threshold Odor Concentrations in Threshold Odor Concentrations in

Air Water

(mg/m ) (mg/l) 3

1,2,4-Trichlorobenzene - 0.005

2,4,6-Trichlorophenol 0.001 -

2,4-Dimethylphenol 0.001 -

Acetophenone 0.01 -

Benzenethiol 0.0005 -

beta-BHC - 0.0003

Chlordane - 0.0000025

Cresol (mixed isomers) 0.001 -

Diphenyl ether 0.01 -

Hexachloro-1,3-butadiene - 0.006

Hexachlorocyclopentadiene - 0.0016

Hexachloroethane - 0.001

Methyl mercaptan 0.0002 -

Nitrobenzene 0.01 -

o-Cresol 0.0003 -

p-Cresol 0.004 -

Source: Verscheuren, Karel, Handbook of Environmental Data on Organic Chemicals, Second Edition, 1983

Because odor problems typically are handled locally and these problems likely do not meet the RCRA

definition of risks meant to be addressed by the hazardous waste management program, EPA does not plan to

investigate this area further following the Scoping Study.
 U.S. Environmental Protection Agency, Office of Air Quality Planning and Standards, Deposition of Air Pollutants to the Great

1

Waters, First Report to Congress, EPA-453/R-93-055, May 1994.

Page 5-4

Exhibit 5-3. Initial List of

Large-Scale Environmental Problems

Air deposition to the Great Waters

Damages from airborne particulates

Global climate change

Potential damages from endocrine disruptors

Red tides

Stratospheric ozone depletion

Tropospheric ozone and photochemical air pollution

Water pollution

5.3 Large-Scale Environmental Problems

EPA considered whether any major large-scale environmental problems (e.g., global climate change,

potential damage from endocrine disruptors) might be caused, at least to some extent, by non-hazardous industrial

wastes. Depending on the types of wastes and on the relative contributions of these wastes to the problem areas,

changes in the hazardous waste characteristics might be one method to help reduce further damages.

EPA began this phase of the Scoping Study by

developing an initial list of major large-scale

environmental problems (or possible problems) that

have potential links to non-hazardous industrial

wastes (see Exhibit 5-3). Several of these problems

overlap considerably with each other and with exposure

and other damage pathways discussed previously. 

Furthermore, EPA recognizes that other environmental

problems have potential links to non-hazardous

industrial waste; however, given the limited

resources available for this Scoping Study, the Agency

chose to limit this analysis to some of the more likely

areas of concern.

Following the development of this list, EPA conducted preliminary evaluations of the problem areas to try

to characterize the contributions to the problems from non-hazardous industrial wastes. Because these problems

are typically characterized by highly complex interactions of a large number of factors, determining the exact

contribution of non-hazardous industrial wastes to each problem is difficult and beyond the scope of this study. 

Instead, EPA was able to conduct only initial evaluations to identify areas that may have a significant

contribution from non-hazardous industrial wastes and thus may warrant further analysis following the Scoping

Study.

For environmental problems with a possible link to non-hazardous industrial wastes, EPA identified (where

possible) the industries and waste streams that could be contributing to the problems and the relevant statutes

and programs that are addressing the areas. The environmental problems evaluated for this Scoping Study are

discussed below in the order (alphabetical) listed in Exhibit 5-3.

5.3.1 Air Deposition to the Great Waters

Pollutants emitted into the atmosphere are transported various distances and can be deposited to aquatic

ecosystems far removed from their original sources. Studies show that significant portions)often greater than 50 1

percent)of pollutant loadings to the Great Waters (i.e., Great Lakes, Lake Champlain, Chesapeake Bay, and coastal

waters) are from atmospheric deposition. Thus, this pathway is an important factor in the degradation of water

quality and the associated adverse health and ecological effects. Because of the mounting concern that air

pollution contributes to water pollution, Congress included Section 112(m), Atmospheric Deposition to Great Lakes

and Coastal Waters, in the Clean Air Act Amendments of 1990.

Both local and distant air emission sources contribute to a pollutant load at a given location. The

sources of concern for the Great Waters primarily include industrial activities and processes involving
Page 5-5

combustion. At present, however, a complete and comprehensive inventory of the locations of particular sources

and the amount of individual toxic pollutants that each source emits to the air is lacking. Nevertheless, EPA has

identified several known air pollutants of concern for Great Waters. Exhibit 5-4 lists these pollutants and

selected U.S. sources. Most pollutants in this exhibit are TC analytes, while a smaller set are chemicals (or

chemical groups) of concern discussed in Chapter 4. Thus, these pollutants are likely candidates for further

analysis as potential gaps in the hazardous waste characteristics.

Exhibit 5-4. U.S. Sources of Air Pollutants of Concern for Great Watersa

Pollutant Sources of Air Emissions

Cadmium and Fossil fuel combustion; aluminum production; cadmium, copper, lead, and zinc smelting; iron and steel production; battery

compounds manufacturing; hazardous waste and sewage sludge incineration; municipal waste combustion; petroleum refining; lime

manufacturing; cement manufacturing; pulp and paper production; combustion of waste oil; pigment manufacturing; soilderived dust; volcanoes

Chlordane Insecticide application; volatilization from soils, water, and treated building foundations due to past insecticide b

application; suspension of eroded soil particles

DDT/DDE Insecticide application; volatilization from soils and water due to past insecticide application b

Dieldrin Insecticide application; volatilization from soils and water due to past insecticide application b

Hexachloro- Manufacturing of chlorine and related compounds; combustion of materials containing chlorine; pesticide manufacturing;

benzene municipal waste combustion; fungicide application; volatilization from soils and water due to past fungicide application b

-HCH Insecticide application; volatilization from soils and water due to past insecticide application b

Lindane Insecticide application; volatilization from soils and water due to past insecticide application b

Lead and Fossil fuel combustion; aluminum production; lead smelting; ferroalloys production; iron and steel production; battery

compounds manufacturing; hazardous waste and sewage sludge incineration; municipal waste combustion; petroleum refining; lime

manufacturing; cement manufacturing; asphalt and concrete manufacturing; pulp and paper production; combustion of waste

oil; paint application; motor vehicles; forest fires; suspension of eroded soil particles; volcanoes b b

Mercury and Fossil fuel combustion; copper and lead smelting; hazardous waste; municipal waste, medical waste, and sewage sludge

compounds incineration; lime manufacturing; cement manufacturing; chlorine and caustic soda manufacturing; paint application;b

suspension of eroded soil particles; erosion from soils and water; volcanoes

PCBs Incineration and improper disposal of PCB-contaminated waste; disposal of waste oil; malfunction of PCB-containing

transformers and capacitors; electrical equipment manufacturing; pulp and paper production; volatilization from soils and

water; municipal solid waste incineration and unregulated combustion

Polycyclic Combustion of plant and animal biomass and fossil fuels; municipal waste combustion; petroleum refining; steel production;

organic matter coke by-product recovery; aluminum production; plywood and particle board manufacturing; surface coating of auto and light

duty trucks; asphalt processing; dry cleaning (petroleum solvent); fabric printing, coating, and dyeing; forest fires
 U.S. Environmental Protection Agency, Office of Research and Development, Strategic Plan for the Office of Research and

2

Development, ORD, EPA/600/R-96/059, May 1996.

Page 5-6

Exhibit 5-4. U.S. Sources of Air Pollutants of Concern for Great Watersa

(continued)

Pollutant Sources of Air Emissions

2,3,7,8-TCDF Hazardous, industrial, municipal, and medical waste and sewage sludge incineration; combustion of fossil fuels and organic

materials containing chlorine; by-product of various metals recovery processes, such as copper smelting; accidental fires

of treated wood products and PCB-containing transformers and capacitors; improper disposal of certain chlorinated wastes;

pesticide production, application, and spills; pulp and paper production; volatilization and erosion of dust from landfill

sites; forest fires

2,3,7,8-TCDD Hazardous, industrial, and medical waste and sewage sludge incineration; municipal waste combustion; combustion of fossil

fuels and organic materials containing chlorine; by-product of various metals recovery processes, such as copper smelting;

accidental fires of treated wood products and PCB-containing transformers and capacitors; improper disposal of certain

chlorinated wastes; pesticide production, application, and spills; pulp and paper production; volatilization and erosion

of dust from landfill sites; forest fires

Toxaphene Insecticide application; volatilization from soils and water due to past insecticide application b

Nitrogen Fossil fuel and other types of combustion; motor vehicles; fertilizer application; animal waste

compounds

 From Table 9 of U.S. EPA, Deposition of Air Pollutants to the Great Waters, supra footnote 1. a

 Not currently a significant source in the U.S. due to manufacturing or use restrictions. b

5.3.2 Airborne Particulates

Airborne particulate matter (PM) is one of the six high-priority research topics identified for the next

few years by the EPA Office of Research and Development (ORD). PM includes dust, dirt, soot, smoke, and liquid 2

droplets directly emitted into the air by sources such as factories, power plants, transportation sources,

construction activity, fires, and windblown dust. Concern regarding PM from non-hazardous industrial waste

includes toxic constituents entrained on particulates. PM is also formed in the atmosphere by condensation or

transformation of emitted gases such as sulfur dioxide, nitrogen oxides, and volatile organic compounds into small

droplets.

Based on studies of human populations exposed to high concentrations of particles (often in the presence

of sulfur dioxide) and on laboratory studies of animals and humans, the major concerns for human health include

effects on breathing and respiratory symptoms, aggravation of existing respiratory and cardiovascular disease,

alterations in the body's defense systems against foreign materials, damage to lung tissue, carcinogenesis, and

premature death. The major subgroups of the populations that appear likely to be most sensitive to the effects of

particulate matter include individuals with chronic obstructive pulmonary cardiovascular disease, individuals

with influenza, asthmatics, the elderly, and children. Particulate matter may injure crops, trees and shrubs, and

may damage metal surfaces, fabrics, and other materials. Fine particulates also impair visibility by scattering

light and reducing visibility. The haze caused by fine particles can diminish crop yields by reducing sunlight.

PM is increasingly being identified as posing a high potential for health and environmental risk and other

potential damages. Nevertheless, EPA does not believe that PM is a significant waste characterization issue but

rather a waste management issue. Furthermore, other programs (e.g., CAA National Ambient Air Quality Standards)
 U.S. Environmental Protection Agency, Office of Policy, Planning, and Evaluation, Environmental Goals for America, with 3

Milestones for 2005 (Draft for Federal Review), June 1996.

 Intergovernmental Panel on Climate Change (IPCC), Climate Change 1995: The Science of Climate Change, Second Assessment Report,

4

Cambridge University Press, 1996.

 IPCC, WGI Technical Support Unit, IPCC Guidelines for National Greenhouse Gas Inventories: Reporting Instructions, Bracknell,

5

U.K., 1995.

Page 5-7

are designed to address this area. Therefore, airborne particulates are not planned for further study as a

potential gap.

5.3.3 Global Climate Change

Evidence is mounting that the increasing concentrations of greenhouse gases (GHGs) will ultimately raise

(and some believe are currently raising) atmospheric and ocean temperatures significantly, which may in turn alter

global weather patterns. Global climate already has changed over the past century, and the balance of evidence 3

suggests a discernible human influence. Climate is expected to continue to change in the future. 4

EPA conducted a brief review of the major anthropogenic sources of the two predominant GHGs, carbon

dioxide (CO ) and methane (CH ), to determine the relative contributions of non-hazardous industrial wastes, 2 4

including their co-disposal with municipal solid waste (MSW). Before describing the results of this review, it is

essential to understand some of the international conventions used to evaluate GHG emissions, as these conventions

have a strong bearing on the results.

The United States and all other parties to the Framework Convention on Climate Change agreed to develop

inventories of GHGs for purposes of developing mitigation strategies and monitoring the progress of those

strategies. The Intergovernmental Panel on Climate Change (IPCC) developed a set of inventory methods to be used

as the international standard. The screening methodology used in this section to evaluate emissions and sinks of 5

GHGs attempts to be consistent with IPCC's guidance.

One of the elements of the IPCC guidance that deserves special mention is the approach used to address CO2

emissions from biogenic sources. For many countries, the treatment of CO releases from biogenic sources is most 2

important when addressing releases from energy derived from biomass (e.g., burning wood), but this element is also

important when evaluating waste management emissions (for example, the decomposition or combustion of grass

clippings or paper). The carbon in paper and grass trimmings was originally removed from the atmosphere by

photosynthesis, and under natural conditions, it would eventually cycle back to the atmosphere as CO2 due to

degradation processes. The quantity of carbon that these natural processes cycle through the earth's atmosphere,

waters, soils, and biota is much greater than the quantity added by anthropogenic GHG sources. But the focus of the

Framework Convention on Climate Change is on anthropogenic emissions emissions resulting from human activities

and subject to human control because these emissions have the potential to alter the climate by disrupting the

natural balances in carbon's biogeochemical cycle.

Thus, for processes with CO emissions, if the emissions are from biogenic materials and the materials are 2

grown on a sustainable basis, then those emissions are considered to simply close the loop in the natural carbon

cycle; that is, they return CO to the atmosphere that was originally removed by photosynthesis. In such cases, the 2

CO2 emissions are not counted (and thus most CO2 emissions from landfills are not counted). On the other hand, CO2

emissions from burning fossil fuels are counted because these emissions would not enter the cycle were it not for

human activity. Likewise, CH4 emissions from landfills are counted, even though the source of carbon is primarily
 Because CH has a higher global warming potential than CO , CH 's incremental global warming potential is counted. 6

4 2 4

 U.S. Environmental Protection Agency, Office of Policy Planning and Evaluation, Inventory of U.S. Greenhouse Gas Emissions and

7

Sinks: 1990-1994, EPA 230-R-96-006, November 1995.

 Ibid. 8

 Ibid. 9

 61 Federal Register 9905, March 12, 1996. 10

Page 5-8

biogenic. CH would not be emitted but for the human activity of landfilling the waste, which creates anaerobic 4

conditions conducive to CH formation. This approach does not distinguish between the timing of CO emissions, 4 2

6

provided that they occur in a reasonably short time scale relative to the speed of the processes that affect global

climate change. That is, as long as the biogenic carbon would eventually be released as CO , it does not matter 2

whether it is released virtually instantaneously (e.g., from combustion) or over a period of a few decades (e.g.,

decomposition on the forest floor).

CO2 accounts for the largest share of U.S. GHG emissions, comprising 1,408 million metric tons of carbon

equivalent (MMTCE) out of total 1994 U.S. emissions of 1,666 MMTCE. Combustion of fossil fuels results in the vast 7

majority of the CO emissions (1,390 MMTCE), with the remainder from industrial processes such as cement 2

production, lime production, limestone consumption (e.g., iron and steel production), soda ash production and

use, and CO manufacture. CO emitted from landfills as a product of both aerobic and anaerobic decomposition of 2 2

organic wastes is not counted, as described above.

Methane is the second most important GHG; U.S. emissions in 1994 were 166 MMTCE. Of the anthropogenic CH 8

sources, the largest is landfills (which contribute 36 percent of the total U.S. methane emissions), agricultural

activities (32 percent), coal mining (15 percent), production and processing of natural gas and oil (11 percent),

fossil fuel combustion (3 percent), and wastewater treatment (0.6 percent).9 As explained above, CH4 from

landfills is counted as an anthropogenic GHG.

The majority of landfill CH4 emissions result from MSW landfills (90 to 95 percent), with the remaining

methane emitted from the disposal of industrial wastes. Methane emissions from large MSW landfills, however, are

currently regulated under EPA's recent New Source Performance Standards and Emissions Guidelines, which require 10

collection and control of landfill gas. Small MSW landfills and industrial waste monofills are not subject to

these new regulations and thus may warrant further investigation. This is particularly true for small landfills

or monofills managing non-hazardous industrial wastes that have a high biochemical oxygen demand (such as wastes

from paper mills and food processing), which have a high potential for generating CH .4

In conclusion, non-hazardous industrial wastes may contribute to GHG emissions to the extent that they

are highly degradable and either are disposed in small landfills (which are not subject to the landfill gas rule)

or are released directly to the atmosphere. The emissions attributable to these wastes are small compared to other

sources of GHGs. Nevertheless, the same highly putrescible wastes that would be of concern when disposed in a

landfill environment are likely to cause taste and odor problems that adversely affect local air and water

quality. To a large degree, the climate change risk (and much of the potential groundwater resource damage) could

be readily averted for highly putrescible wastes by biological pretreatment prior to land disposal to reduce the

potential for (a) methane formation and (b) production of odiferous compounds generated in an anaerobic

environment. Further research could be conducted in this area to determine whether the potential contribution of
 Several other terms are and have been used, such as persistent organic pollutants, which actually are a subset of PBTs. 11

 U.S. Environmental Protection Agency, Office of Solid Waste, "The Waste Minimization National Plan," EPA530-R-94-045, 1994.

12

 Center for the Study of Environmental Endocrine Effects, Environmental Endocrine Effects: An Overview of the State of 13

Scientific Knowledge and Uncertainties, Discussion Draft (first released for public comment at the Sept. 22, 1995 public meeting

of the Science Advisory Board of the U.S.-Canada International Joint Commission), Washington, DC (also available on the World Wide

Web at http://www.endocrine.org).

 Arnold, SF, Klotz, DM, Collins, BM, Vonier, PM, Guillette Jr., LJ, and McLachlan, JA, "Synergistic Activation of Estrogen

14

Receptor with Combinations of Environmental Chemicals," Science, 272 (5267):1489, June 7, 1996; and Suplee, C, "`Environmental

Estrogens' May Pose Greater Risk, Study Shows," The Washington Post, p. A4, June 7, 1996.

 Strategic Plan for the Office of Research and Development, supra footnote 2. 15

Page 5-9

non-hazardous industrial wastes to GHG emissions could be significant. However, given the current coverage of

this problem area by other programs besides Subtitle C of RCRA, EPA does not plan to pursue global climate change

within the context of the hazardous characteristics at this time.

5.3.4 Potential Damages from Endocrine Disruptors

Over the past decade, increased attention has been given to a class of chemicals with high persistence,

bioaccummulation potential, and toxicity. These chemicals, often referred to as PBTs, include a wide range of 11

substances, generally several metals and a variety of organic compounds. EPA's involvement in PBT research and

regulation has encompassed many programs. One of these programs, waste minimization, developed the Waste

Minimization National Plan. This plan established a national goal to reduce the most persistent, 12

bioaccumulative, and toxic chemicals in hazardous wastes by 25 percent by the year 2000 and by 50 percent by the

year 2005. Currently many international organizations, including the North American Commission for Environmental

Cooperation and various United Nations groups, are debating PBT public policy and ultimately could generate

binding commitments (e.g., treaties) that could affect U.S. national policy on PBTs. For example, an initial list

of 12 PBTs is being considered for control under an international protocol.

Recently, interest in PBTs has escalated due to the growing attention on a subgroup of these chemicals

called "endocrine disruptors" (EDs). EDs are substances that have the potential to interfere with hormonal

systems in ecological and human receptors. The results of such interference might include adverse reproductive or

developmental effects, certain kinds of cancers, learning and behavioral problems, and immune system

deficiencies. Recent concern has focused on the potential synergistic effects of EDs. 13 14

Significant scientific debate still exists regarding which chemicals are EDs and the degree to which EDs

have caused or have the potential to cause adverse human health and environmental effects. This debate has

prompted great interest in researching the scope of ED impacts. For example, the study of EDs is one of the six

high-priority research topics identified by EPA's Office of Research and Development (ORD) for the next few

years. It has also been made a high priority by the U.S. chemical industry; the Chemical Industry Institute for 15

Toxicology (CIIT) has reprogrammed much of its research budget into this area. To the extent that the impact of EDs

on the environment are largely unknown, these chemicals may represent a substantial gap in the hazardous waste

regulations.
 Colborn, T., vom Saal, F.S., and Soto, A.M., "Developmental Effects of Endocrine-Disrupting Chemicals in Wildlife and Humans,"

16

Environmental Health Perspectives, 101(5):378-384, 1993; Guillette, L.J., Crain, D.A., Rooney, A.A., and Pickford, D.B.,

"Organization Versus Activation: The Role of Endocrine-Disrupting Contaminants (EDCs) During Embryonic Development in Wildlife,"

Environmental Health Perspectives, 103(Supp 7):157-164, 1995.

 Guillette, L.J., Gross, T.S., Masson, G.R., Matter, J.M., Percival, H.F., and Woodward, A.R, "Developmental Abnormalities of

17

the Gonad and Abnormal Sex Hormone Concentrations in Juvenile Alligators From Contaminated and Control Lakes in Florida,"

Environmental Health Perspectives, 102(8):680-688, 1994.

 Fox, G.A., "Epidemiological and Pathobiological Evidence of Contaminant-Induced Alterations in Sexual Development in Free18

Living Wildlife," in Colborn, T., and Clement, C. (eds.), Chemically-Induced Alterations in Sexual and Functional Development: The

Wildlife/Human Connection, Princeton Scientific Publishing, Princeton, NJ, pp. 147-158, 1992.

 Fry, D.M., "Reproductive Effects in Birds Exposed to Pesticides and Industrial Chemicals," Environmental Health Perspectives,

19

103(Supp 7):165-171, 1995.

 Sumpter, J.P., and Jobling, S., "Vitellogenesis as a Biomarker For Estrogenic Contamination of the Aquatic Environment," 20

Environmental Health Perspectives, 103(Supp 7):173-178, 1995.

 Ibid.

21

Page 5-10

Notwithstanding the current debate, recent review articles summarize convincing evidence that a variety

of chemical pollutants can act as endocrine disruptors in wildlife populations. Some specific examples include 16

the following:

Reptiles. Researchers found that the reproductive development of alligators from Lake

Apopka, Florida was severely impaired, apparently due to DDE, a metabolite of DDT and

dicofol. The lake is located adjacent to an EPA Superfund site where a dicofol spill 17

had occurred. The specific adverse effects included decreased testosterone and

abnormal testicular cells in males and increased estrogen and altered ovaries

(increased polyovular follicles and polynuclear oocytes) in females.

Birds. A number of researchers have documented severely impaired reproductive success

in herring gulls from the Great Lakes. Some specific observations include large clutch 18

sizes (attributed to nest sharing by two females), female-female pair bonds, embryonic

and chick mortality, and altered nest defense and incubation behavior. These effects

were associated with high levels of organochlorines (e.g., DDT, dioxins, and mirex) in

the 1960s and early 1970s. Reproductive success increased as levels of these compounds

declined in the late 1970s and 1980s. Organochlorines that have been identified as

estrogenic to bird embryos in laboratory studies include DDT and methoxychlor.19

In these cases, some of the causative agents appear to be organochlorine pesticides that are no longer

produced (e.g., DDT) yet persist in the environment due to the nature of their chemical/physical properties. 

Although these chemicals are not generally expected to be components of non-hazardous industrial wastes, a number

of similar chemicals currently used in industry have demonstrated similar endocrine disrupting properties in

laboratory studies. These EDs are often present in treated sewage effluent, and are likely to be components of 20

non-hazardous industrial waste.

A recent field study found that effluent from sewage treatment works induced vitellogenin synthesis in

male fish, indicating that the effluent is estrogenic. The effects were pronounced and occurred at all sites 21
 Arnold, S.F., et al., supra footnote 14. 22

 Munkittirck, K.R., Portt, C.B., Van Der Krakk, G.J., Smith, I.R., and Rokosh, D.A., "Impact of Bleached Kraft Mill Effluent on

23

Population Characteristics, Liver MFO Activity, and Serum Steroid Levels of A Lake Superior White Sucker (Catostomus Commersoni)

Population, Can. J. Fish. Aquat. Sci., 48:1371-1380, 1991.

 Davis, W.P., and Bortone, S.A., "Effects of Kraft Mill Effluent on the Sexuality of Fishes: An Environmental Early Warning?"

24

in Colborn, T., and Clement, C. (Eds.), Chemically-Induced Alterations in Sexual and Functional Development: The Wildlife/Human

Connection, Princeton Scientific Publishing, Princeton, N.J., pp. 113-127, 1992.

Page 5-11

tested. The identity of the chemical or chemicals in the sewage effluent causing the effects is not known,

however. A number of chemicals known to be present in sewage effluent were tested for estrogenic effects in fish. 

These chemicals included nonylphenol, octylphenol, bisphenol-A, DDT, and PCBs. Furthermore, a mixture of

different estrogenic chemicals was found to be considerably more potent than each of the chemicals when tested

individually, a finding that recently was replicated.22

In addition to the effects described above, other documented endocrine disrupting effects in wildlife

populations from industrial effluents have unknown causative agents. For example, kraft mill effluent caused a

variety of effects in two fish species: white suckers and mosquitofish. Lake Superior white suckers collected 23

from a site receiving primary-treated bleached kraft mill effluent exhibited increased age to maturity, smaller

gonads, lower fecundity with age, and an absence of secondary sex characteristics. Masculinization of female

mosquitofish was noted downstream from the discharge of kraft mill effluent in Elevenmile Creek in Florida.24

Several of the chemicals identified in this section are also identified in Chapter 4 as known or possible

non-hazardous industrial waste constituents. Some of the relevant chemical groups are described in more detail

below.

Alkylphenol Compounds. Alkylphenol-polyethoxylates are non-ionic surfactants commonly

used in industrial and domestic detergents as well as some shampoos and cosmetics. 

Alkylphenols are used as antioxidants in some clear plastics. Alkylphenolpolyethoxylates are biodegraded to alkylphenols during sewage treatment. These

compounds persist in rivers and their sediments and can migrate to groundwater. These

compounds also have the ability to bioconcentrate in animals.

Bisphenol-A. This compound is used to manufacture polycarbonate, a component in a wide

array of plastics and other polymer products. Bisphenol-A also is used to manufacture

epoxy resins, which are components of a variety of lacquers and adhesives.

Phthalates. Phthalates are one of the most abundant man-made chemicals in the

environment. Phthalate esters are used in the production of various plastics. 

Butylbenzyl phthalate (BBP) also is used in the production of vinyl floor tiles,

adhesives, and synthetic leather. Di-n-butylphthalate (DBP) is a common plasticizer in

food-packaging materials and polyvinyl chloride. Thousands of tons of plastics are

disposed of annually in landfills, thus possibly enabling phthalate esters to migrate

into soil and groundwater. These compounds have the ability to bioconcentrate in

animals.

As seen in Chapter 4, other categories of chemicals with ED characteristics (e.g., heavy metals) are present in

wastes generated by numerous industries.
Page 5-12

In conclusion, the evidence that alkylphenols, bisphenol-A, and phthalates are endocrine disruptors is

based mainly on laboratory studies. The effects of these chemicals on wildlife populations is not known. Based on

the endocrine disrupting effects of organochlorines on populations of fish, birds, reptiles, and mammals,

however, it is possible that alkylphenols, bisphenol-A, phthalates, and other chemicals also could have endocrine

disrupting effects in wildlife. Furthermore, as seen in Chapter 4, it is likely that some of these chemicals

(e.g., the phthalates) are also components of several non-hazardous industrial wastes.
 Broad, W.J., "A Spate of Red Tides Menaces Coastal Seas," The New York Times, August 27, 1996; and Lewitus, A.J., R.V. Jesien,

25

T.M. Kana, J.M. Burkholder, H.B., Jr., Glasgow, E. May, "Discovery of the Phantom Dinoflagellate in Chesapeake Bay," Estuaries

18(2):373-378, 1995.

 Ikeda, T., T. Matsumoto, H. Kisa, Y. Ishida, A. Kawai, "Analysis of Growth Limiting Factors Causative of Freshwater Red Tide

26

by Dinoflagellate Peridinum Bipes F. Occultatum," Jap.-J.-Limnol.-Rikusuizatsu, 54(3): 179-189, 1993; Jiang, G., "The Preliminary

Study on The Eutrophication and the Red Tide in the South Coastal Area of Zhejiang, Donghai-Mar.-Sci.-Donghai-Haiyang, 11(2): 55-6,

1993; Okaichi, T., S. Montani, A. Hasui, "The Role of Iron in the Outbreaks of Chattonella Red Tide," Red Tides: Biology,

Environmental Science, and Toxicology, Proceedings of the First International Symposium on Red Tides, held in November 10-14, 1987,

in Takamatsu, Kagawa-Prefecture, Japan, p. 353-356; and "Thousands of Gulf Fish Die; Red Tide Is Probable Cause," The New York Times,

September 1996.

 Skojoldal, H.R., "Eutrophication and Algal Growth in the North Sea," Mar. Environ. Cent., Mar. Res., Bergen-Nordnes, Norway,

27

p. 445-478, undated.

 Wu, R.S.S., "The Environmental Impact of Marine Fish Culture: Towards a Sustainable Future," International Conference on Marine

28

Pollution and Ecotoxicology, held in Hong Kong, Jan. 22-26, 1995, Vol. 31, no. 4-12, p. 159-166; and Broad, supra footnote 25.

 Personal communications with Tony Amos, University of Texas Marine Science Institute, Port Aransas, Texas, and Daniel Baden,

29

School of Marine and Atmospheric Science, Miami, Florida, on October 22, 1996.

 Personal communication with Scott Rippey, U.S. Food and Drug Administration, October 21, 1996. 30

Page 5-13

5.3.5 Red Tides

Red tides are rapid increases in growth (i.e., blooms) of freshwater and marine plants called

dinoflagellates, which typically are microscopic unicellular organisms that photosynthesize but also have tails

for movement. A red tide occurs when dinoflagellates multiply rapidly due to optimal growth conditions such as

abundant dissolved nutrients and sunlight. They produce toxins to defend themselves from zooplankton and other

aquatic grazers. The term red tides includes orange, brown, red, and even green blooms.

Shellfish, such as clams, mussels, oysters, or scallops, consume dinoflagellates and can accumulate the

toxins in their flesh. Usually, the shellfish are not severely affected, but they can contain enough toxins to

sicken and even kill humans. The recently discovered Pfiesteria piscida is one of many species of dinoflagellate

that causes red tides. It produces potent toxins that cause bleeding sores in fish and can adversely affect humans

via air releases. It recently has caused massive fish kills in the Neuse and Pamlico Rivers in North Carolina.25

Several case studies have shown the relationship between the levels of nutrients, such as phosphorus,

nitrogen, silicon, and iron, in coastal and fresh waters, and the proliferation of red tides. Studies also have 26

shown that the high levels of nutrients and eutrophication of the water (which favors the development of red tides)

are often caused by surrounding human development and industrial and domestic wastewaters. Recent development 27

of agribusiness and factory farms in coastal areas releases wastes with high levels of nutrients into the water

that may favor red tides.28

Some researchers believe that the occurrence of red tides has been increasing over the years, although

improvements in the monitoring and reporting of red tides could account for this. Even if such an increase were 29

occurring, however, a commensurate increase in human poisoning from ingestion of shellfish contaminated with

dinoflagellate toxins has not been seen, likely because of the improved monitoring and reporting of red tides.30

Notwithstanding the potential link between red tides and constituents that are often found in nonhazardous industrial waste, little if any evidence has been found during this review concerning the degree to
 Environmental Goals for America, with Milestones for 2005 (Draft for Federal Review), supra footnote 3. 31

 The majority of these documents were developed to support the first key substitutes rulemaking (59 Federal Register 13044, March

32

18, 1994).

Page 5-14

which these wastes may be contributing to the problem. Therefore, for the purposes of this hazardous waste

characteristic gaps study, EPA does not plan to conduct further research in this area at this time.

5.3.6 Stratospheric Ozone Depletion

The stratospheric ozone layer protects living organisms from damaging solar ultraviolet radiation (UVB). Depletion of the ozone layer means a greater amount of UV-B radiation is reaching the earth's surface, which

increases human skin cancers and cataracts, impairs human immune systems, reduces crop yields, and damages plant

and animal life. Several industrial chemicals, including chlorofluorcarbons (CFCs), halons, carbon 31

tetrachloride, methyl chloroform, and methyl bromide, are known to be stratospheric ozone-depleting substances

(ODSs).

For many years, ODSs have been used in a variety of manufacturing and other activities. With the

ratification of the Montreal Protocol and its subsequent amendments and adjustments, the United States agreed to

eliminate the production of ODSs by January 1, 1996 (with a few exceptions). In addition, the disposal of ODSs is

tightly controlled in order to prevent further ozone depletion. Thus, EPA believes that, for purposes of the

hazardous waste characteristic gaps analysis, ozone-depleting and non-ozone-depleting risks (e.g., via

inhalation during combustion or from groundwater during land disposal of residuals) do not need to be examined

further at this time.

In a related area (though not necessarily a large-scale environmental problem), the ultimate elimination

of ODSs has spurred the development of a large number of alternative chemicals and technologies to replace ODSs. 

In the United States, the Significant New Alternatives Policy (SNAP) Program was put in place by EPA to ensure that

alternatives implemented to replace ODSs are not themselves environmentally harmful or unsafe for workers and

others who might be exposed to the new chemicals. As part of this program, EPA has developed a series of SNAP

Technical Background Documents to address the ODS substitutes. Before a new alternative is developed and 32

introduced into interstate commerce, EPA must review the alternative and categorize it as acceptable, acceptable

with limitations, or unacceptable, based on a risk screen of the alternative's characteristics. This risk screen

addresses global atmospheric effects of the alternative, as well as worker, consumer, and general population

exposure. Thus, groundwater damage and other more local adverse effects of the alternative from solid waste

generation and management are included in this screening process. Therefore, EPA does not intend to conduct

further investigations into the solid waste and hazardous characteristics implications of the SNAP-approved

alternatives at this time.
 U.S. Environmental Protection Agency, Office of Air Quality Planning and Standards, National Air Quality and Emission Trends

33

Report, 1991, EPA 454/R-95-014, October 1995.

 U.S. Environmental Protection Agency, Office of Water, National Water Quality Inventory Report to Congress, 1994. 34

 In excess, nutrients can create a chain of impacts that include algal blooms, fish kills, foul odors, and weed growth. 35

Page 5-15

5.3.7 Tropospheric Ozone and Photochemical Air Pollution

Photochemical reactions between organic chemicals, nitrogen oxides, and other oxidizing agents can

produce ozone and photochemical oxidant pollution. Such pollution occurs in areas where sunlight is intense,

emissions of nitrogen oxides and volatile organic compounds (VOCs) are high, and atmospheric conditions impede

regional air circulation. Some chemicals emitted from non-hazardous industrial waste management units could

contribute to the total emissions of volatile organics in some locations. As shown in Exhibit 4-2, many

potentially reactive VOCs have been found as constituents of non-hazardous industrial wastes. This contribution,

however, appears to be quite small. Recent emissions studies have shown that, in most municipal areas where 33

photochemical pollution is a problem, mobile and utility sources contribute the largest single portion of these

emissions, with emissions from other sources generally contributing a smaller amounts. Thus, the Agency did not

pursue this issue further as a potential gap in the hazardous waste characteristics.

5.3.8 Water Pollution

Based on information reported to EPA by States, Tribes, and other jurisdictions with water quality

responsibilities, about 40 percent of the Nation's surveyed rivers, lakes, and estuaries are not clean enough for

basic uses such as fishing or swimming. Polluted runoff from rainstorms and snowmelt is the leading cause of this 34

impairment. As seen below, the causes of this damage are highly varied.

Rivers. Runoff from agricultural lands is the largest source of pollution for rivers. 

Municipal sewage treatment plants, storm sewers/urban runoff, and resource extraction

also are among the leading sources. Bacteria, which can cause illnesses in swimmers and

others involved in water-contact sports, are the most common pollutants impacting

rivers. Siltation, nutrients (such as phosphates and nitrates), oxygen-depleting 35

substances, and metals are the other leading causes of river pollution.

Lakes. As with rivers, runoff from agricultural lands is the largest source of

pollution. Municipal sewage treatment plants, storm sewers/urban runoff, and

unspecified nonpoint sources also lead the list. Leading causes of lake pollution are

nutrients, siltation, oxygen-depleting substances, metals, and suspended solids.

Estuaries. Storm sewers and urban runoff are the leading sources of pollution in

estuaries. Municipal sewage treatment plants, agriculture, industrial point sources,

and petroleum activities also lead the list. Nutrients, such as phosphates and

nitrates, are the most often reported pollutant in estuaries. Other leading causes of

pollution are bacteria, oxygen-depleting substances, and oil and grease.

Although non-hazardous industrial wastes contribute to this pollution to some degree (e.g., via sewage

treatment and industrial point and non-point sources), it is unclear whether this contribution constitutes an

actual gap in the hazardous waste characteristics. For example, significant changes in EPA's definition of solid

waste would be needed before the hazardous waste characteristics could be used to prevent some of these wastes from
 40 CFR 261.4(a)(2). This exemption applies only to the actual point source discharge. It does not exclude industrial wastewater

36

while they are being collected, stored, or treated before discharge; nor does it exclude sludges generated by industrial wastewater

treatment.

 40 CFR 261.4(b). This exemption applies to wastes that are returned to the soil as fertilizers, such as animal manures and the

37

unused portion of crops.

 Some of these controls currently are being implemented. For example, a recent final National Pollutant Discharge Elimination

38

System(NPDES) storm water multi-sector general permit was published for industrial activities (60 Federal Register 50803, September

29, 1995).

Page 5-16

entering surface waters and resulting in risks or damage. Industrial wastewaters that are point source discharges

subject to regulation under the Clean Water Act are exempt from the definition of solid waste. Many of the wastes 36

from agriculture one of the largest contributers to water pollution from runoff are exempt from the definition

of hazardous waste (although they are solid wastes). Alternatively, EPA could increase controls on point and 37

non-point sources of water pollution via other programs. Thus, for purposes of the hazardous characteristic 38

scoping study, EPA does not plan to research this area further at this time.
Page 5-17

CHAPTER 5. POTENTIAL GAPS ASSOCIATED WITH NATURAL RESOURCE DAMAGES AND LARGE-SCALE

ENVIRONMENTAL PROBLEMS .......................................... 5-1

5.1 Damage to Groundwater Resources .......................................... 5-1

5.2 Damage to Local Air Quality from Odors ..................................... 5-2

5.3 Large-Scale Environmental Problems ........................................ 5-4

5.3.1 Air Deposition to the Great Waters ................................... 5-4

5.3.2 Airborne Particulates .............................................. 5-6

5.3.3 Global Climate Change ............................................. 5-7

5.3.4 Potential Damages from Endocrine Disruptors .......................... 5-9

5.3.5 Red Tides ...................................................... 5-13

5.3.6 Stratospheric Ozone Depletion ...................................... 5-14

5.3.7 Tropospheric Ozone and Photochemical Air Pollution ................... 5-15

5.3.8 Water Pollution .................................................. 5-15
Page 5-18

Exhibit 5-1 Constituents/Properties with SMCLs Found in Release Descriptions ............... 5-2

Exhibit 5-2 Chemicals from Release Descriptions with Low Odor Thresholds .................. 5-3

Exhibit 5-3 Initial List of Large-Scale Environmental Problems ............................. 5-4

Exhibit 5-4 U.S. Sources of Air Pollutants of Concern for Great Waters ...................... 5-5
 U.S. Environmental Protection Agency, Office of Solid Waste, Identifying Higher-Risk Wastestreams in the Industrial D 1

Universe: The State Experience, draft prepared by Science Applications International Corporation and Kerr & Associates, Inc.,

July 30, 1993.

Page 6-1

CHAPTER 6. STATE EXPANSIONS OF THE TOXICITY

CHARACTERISTIC AND LISTINGS

States may adopt hazardous waste regulations that are broader or more stringent than federal RCRA

Subtitle C regulations. A number of states have done so by regulating additional wastes as hazardous. For

example, states have:

Expanded the ignitability, corrosivity, or reactivity (ICR) characteristics;

Expanded the toxicity characteristic (TC);

Listed wastes as hazardous that are not hazardous under the federal rules; and

Restricted exemptions from the federal program.

These expansions beyond the federal hazardous waste identification rules reflect state judgments about gaps in the

federal program and thereby constitute potential gaps that may merit further investigation.

EPA has identified examples of such expansions by using readily available information on state hazardous

waste identification rules. In 1992, the EPA Office of Solid Waste examined state hazardous and non-hazardous

industrial waste programs in 32 states. The study identified "state only" hazardous wastes, as well as high-risk 1

designations for non-hazardous wastes. For the purposes of this Scoping Study, EPA used data from this report and

briefly reviewed current hazardous waste regulations of eight states: California, Michigan, New Hampshire,

Oregon, Rhode Island, Texas, Washington, and New Jersey.

The first three sections of this chapter address state expansion of the TC, state only hazardous waste

listings, and state restrictions on exemptions from the federal regulations, respectively. (State expansions of

the ICR characteristics are addressed in Chapter 3.) In addition, Section 6.4 summarizes the findings of the

chapter.

6.1 State Expanded Toxicity Characteristics

States have expanded the federal toxicity characteristic by:

Adding constituents to the list of TC analytes;

Establishing regulatory levels for TC analytes that are more stringent than federal

levels;

Specifying alternative tests for identifying toxic hazardous waste; and

Using alternative approaches (other than listing constituents and regulatory levels) to

identify toxic hazardous wastes.
 New Jersey had also added a TC regulatory level for PCBs, but the State recently adopted the federal regulations by reference 2

and will now use the same characteristics and listings as the federal program. A number of states have added PCB wastes to their

hazardous waste listings.

 Identifying Higher-Risk Wastestreams in the Industrial D Universe: The State Experience, supra footnote 1 at pages 20A-B. 3

 Ibid., pages 8-14. 4

Page 6-2

California, Michigan, and Washington have added constituents to the list of TC analytes, as shown in

Exhibit 6-1. Both California and Michigan have added zinc, and both California and Washington have added PCBs.2

Other additional constituents include certain metals, pesticides, dioxins, and potential carcinogens. An example

of a state regulatory level that is lower that the federal TC level is California's regulatory level of 1.7 mg/l for

pentachlorophenol (versus 100 mg/l under the federal TC).

As discussed in Section 3.6, California requires use of the Wet Extraction Test (WET) in addition to the

TCLP. Use of the WET test identifies several metal-containing wastes as hazardous that are generally not

identified as hazardous using the TCLP. These wastes include spent catalysts from the petroleum refining and food

industries and metal dusts, metal sludges, and baghouse wastes from industries including fabricated metals,

leather and apparel, electric and electronic products, primary metals, motor vehicles, transportation equipment,

chemicals and allied products, and others.3

Both California and Washington have established toxicity criteria for wastes based on acute oral LD50,

acute dermal LD50, acute inhalation LC50, and acute aquatic 96-hour LC50 (see Exhibit 6-2). A waste is designated

hazardous if a representative sample of the waste meets any of the acute toxicity criteria. For example,

Washington specifies rat and fish (for acute aquatic toxicity) bioassay tests in a State test methods manual. 

Generators must either test a representative sample of the waste or use their knowledge of waste constituents and

the literature regarding toxicity of those constituents to determine if the waste meets any of the acute toxicity

criteria.

Finally, California's regulations state that a waste exhibits the characteristic of toxicity if the

waste, based on representative samples, "has shown through experience or testing to pose a hazard to human health

or environment because of its carcinogenicity, acute toxicity, chronic toxicity, bioaccumulative properties or

persistence in the environment" (22 CCR 66261.24(a)(8)). This broad provision tends to shift the burden of

identifying toxic wastes to the generator, because in the absence of specific state criteria (e.g., constituents

and regulatory levels) the generator is responsible for being aware of experience or tests that show a waste poses

a hazard.

6.2 State Only Listings

In addition to expanded characteristics, some states have listed state only hazardous wastes. The most

common state-only listed wastes are PCBs and waste oil. At least four states include additional "F" Wastes; three

include additional "K" wastes; five include additional "P" wastes; and six include additional "U" wastes. 

Examples of state listed wastes include but are not limited to the following:4
Page 6-3

Exhibit 6-1

State Toxicity Characteristics:

Additional Constituents and More Stringent Regulatory Levels

CALIFORNIA

Constituent Regulatory Level (mg/l in leachate unless otherwise

noted)

antimony 15

aldrin 0.14

asbestos 1 percent

beryllium 0.75

chromium (VI) 5

chromium (III) 560

cobalt 80

copper 25

DDT, DDE, DDD 0.1

2,4-dichlorophenoxyacetic acid 10

dieldrin 0.8

dioxin (2,3,7,8-TCDD) 0.001

fluoride salts 180

kepone 2.1

lead compounds, organic 13 mg/kg

mirex 2.1

molybdenum 350

nickel 20

pentachlorophenol 1.7 (lower regulatory level than federal)

PCBs 5

thallium 7

2,4,5-trichlorophenoxypropionic acid 1

vanadium 24

zinc 250

Any of the following substances at a single or combined concentration equal to or exceeding

0.001 percent by weight:

2-acetylaminofluorene (2-AAF) 3,3,-dichlorobenzidine and its salts (DCB)

acrylonitrile 4-dimethylaminoazobenzene

4-aminodiphenyl ethyleneimine (EL)

benzidine and its salts alpha-naphthylamine (1-NA)

bis(chloromethyl) ether (BCME) beta-naphthylamine (2-NA)

methylchloromethyl ether 4-nitrobiphenyl

1,2-dibromo-3-chloropropane (DBCP) n-nitrosodimethylamine (DMN)

beta-propiolactone (BPL) vinyl chloride (VCM)
Page 6-4

Exhibit 6-1 (continued)

State Toxicity Characteristics:

Additional Constituents and More Stringent Regulatory Levels

MICHIGAN

Constituent Regulatory Level (mg/l)

aflatoxin 1

copper 100

dioxin (1,2,3,4,7,8-HxCDD) 1

dioxin (1,2,3,6,7,8-HxCDD) 1

dioxin (1,2,3,7,8,9-HxCDD) 1

dioxin (1,2,3,7,8-PoCDD) 1

dioxin (2,3,7,8-TCDD) 1

furan (2,3,7,8-TCDF) 1

zinc 500

WASHINGTON

Constituent Regulatory Level (mg/l)

PCBs 2

Exhibit 6-2

State Toxicity Criteria Applied to Whole Waste

(Representative Sample)

CALIFORNIA

acute oral LD50 < 5,000 mg/kg

acute dermal LD50 < 4,300 mg/kg

acute inhalation LC50 < 10,000 ppm

acute aquatic 96h LC50 < 500 mg/l

WASHINGTON

acute oral LD50 < 5,000 mg/kg

acute dermal LD50 < 20,000 mg/kg

acute inhalation LC50 < 200 mg/l

acute aquatic 96h LC50 < 1,000 mg/l

RHODE ISLAND

acute oral LD50 < 5,000 mg/kg

OREGON

acute aquatic 96h LC50 < 250 mg/l (only includes certain pesticide residues)
 Ibid.

5

Page 6-5

In California, wastes containing any of almost 800 listed materials are presumed

hazardous, unless proven through testing not to exhibit any of California's criteria for

identifying hazardous waste.

Maine has listed certain wastes from the production of linuron and bromacil, and has

listed proposed additions to the federal list of hazardous wastes.

Maryland has listed 9 specific chemical warfare agents.

Michigan has added certain chemical production wastes to its "K" or specific source

list, and has listed many state-only "U" wastes including organics, inorganics in

particle form, pharmaceuticals (e.g., phenobarbital), chemical warfare agents, and

herbicides.

New Hampshire has added a number of wastes to its "F" or non-specific source list,

including certain wastes from industrial painting operations and from metals recovery

operations.

Oregon has listed certain pesticide residues and certain blister agents and nerve gas.

6.3 State Restrictions on Exemptions

Another way that states have expanded the universe of wastes they regulate as hazardous is by choosing not

to adopt exemptions in the federal regulations. Examples include but are not limited to the following:5

Colorado does not recognize exemptions for certain injected groundwater that exhibits

the TC and is reinjected pursuant to free phase hydrocarbon recovery operations at

petroleum facilities (40 CFR 261.4(b)(11)), certain used chlorofluorocarbon (CFC)

refrigerants that are reclaimed for further use (40 CFR 261.4(b)(12)), or non-terne

plated used oil filters (40 CFR 261.4(b)(13)).

Connecticut, New Hampshire, Oregon, and Washington do not include exemptions for

certain chromium-bearing wastes from leather tanning and finishing (40 CFR

261.4(b)(6)(ii)).

Maine does not recognize exemptions at 40 CFR 261.4(b)(6) through (13). These include:

-- TC chromium wastes where chromium in the waste is nearly exclusively trivalent

chromium;

-- certain chromium-bearing wastes from leather tanning and finishing;

-- specified mining and mineral processing wastes;

-- cement kiln dust;

-- certain arsenical-treated wood wastes;

-- petroleum contaminated media and debris that fail the TC;

-- certain injected groundwater;

-- used CFC refrigerants; and

-- non-terne plated used oil filters.
Page 6-6

Massachusetts, New York, and North Dakota do not recognize exemptions at 40 CFR

261.4(b)(10) through (13). (These wastes include the last four wastes named directly

above.)

6.4 Summary

Some states appear to be regulating a significant number of wastes as hazardous that are not covered under

federal RCRA regulations. Moreover, a few states have taken different approaches to identifying characteristic

hazardous wastes. In particular, California and Washington regulations go beyond constituent-by-constituent

definitions and apply acute toxicity criteria to the whole waste. State expansions of hazardous waste

identification regulations reflect state judgment about gaps in the federal program. State expansions have filled

these gaps, but only in the specific states with such expansions. Such potential gaps apparently are not being

filled in the remaining states that have not expanded the federal hazardous waste definitions.
Page 6-7

CHAPTER 6. STATE EXPANSIONS OF THE TOXICITY CHARACTERISTIC AND LISTINGS . . 6-1

6.1 State Expanded Toxicity Characteristics ...................................... 6-1

6.2 State Only Listings ....................................................... 6-2

6.3 State Restrictions on Exemptions ........................................... 6-5

6.4 Summary ............................................................... 6-6
Page 6-8

Exhibit 6-1 State Toxicity Characteristics: Additional Constituents and More Stringent

Regulatory Levels ........................................................ 6-3

Exhibit 6-2 State Toxicity Criteria Applied to Whole Waste (Representative Sample) ........... 6-4
Page 7-1

CHAPTER 7. SUMMARY OF POTENTIAL GAPS

 This chapter reviews the broad categories of potential gaps identified in the previous three chapters. 

Different ways of organizing the potential gaps are discussed, and a single comprehensive list of the potential

gaps is presented. This review lays the groundwork for evaluating the significance of the potential gaps in the

following three chapters.

7.1 Organization of the Analysis of Potential Gaps

EPA has identified five categories of potential gaps in the hazardous waste characteristics using

different approaches in each area:

ICR Characteristics. EPA identified potential gaps associated with these

characteristics by reviewing the original 1980 rulemaking record and comparing the ICR

definitions and test methods to approaches taken to controlling similar hazards under

other federal and state regulatory schemes.

TC Characteristic. The Agency identified potential gaps associated with this

characteristic by examining the properties of the TC analytes to determine how they

could pose hazards to human health or the environment.

Non-TC Chemicals. In contrast with the prior step, EPA began with a set of properties

(including the potential to appear in non-hazardous industrial wastes) and then

identified individual chemicals and groups of chemicals that could constitute potential

gaps in the characteristics.

Natural Resource Damages and Large-scale Environmental Problems. The Agency examined

evidence of possible gaps using a hybrid approach that considered potential gap

chemicals on the basis of their hazardous properties (e.g., endocrine disruption,

stratospheric ozone depletion) and reviewed other potential gaps starting from possible

risks to the environment, which, in turn, implied that certain waste constituents might

be of concern.

State Expansion of TC and State Listings. EPA reviewed how states have expanded their TC

and listed as hazardous certain wastes that are not hazardous under the federal rules. 

These expansions reflect state judgments about gaps in the federal rules and thereby

constitute potential gaps for this Scoping Study.

The potential gaps presented in the following section are organized primarily by the major categories

identified above. Where appropriate, these categories are subdivided into groups of chemicals posing similar

types of hazards, and occasionally are subdivided even further by specific hazardous properties or exposure

pathways of concern. Some of the potential gaps overlap. For example, endocrine disruptors appear among the

concerns associated with the non-TC analytes as well as in a category by themselves under large-scale

environmental risks. Although this overlap is inevitable, the potential gaps have been organized so as to

minimize it, without omitting any potentially significant gaps.
Page 7-2

EPA considered other methods of classifying the potential gaps for purposes of further analysis. Gaps

could be identified, for example, in terms of individual chemicals and their specific properties and hazards. 

Alternatively, the gaps could be organized around groups of chemicals with specific hazardous properties or types

of risks. EPA rejected these approaches for purposes of this Scoping Study as impractical because too many

individual chemicals or groups of chemicals, risks, and pathways are involved. In addition, defining potential

gaps in categories that do not parallel the approaches used to identify such gaps would make it more difficult to

appreciate the evidence and uncertainty associated with each potential gap.

7.2 Summary of Potential Gaps

Exhibit 7-1 lists the potential gaps in the hazardous waste characteristics identified by EPA in the

preceding chapters. The individual gaps are organized according to the section or chapter in which they are

discussed, with reference to specific chemical classes, exposure pathways, or types of risks, as appropriate. 

Potential gaps are evaluated in the following chapters in order to assess their potential significance in terms of

potential risks to health and the environment. Because of data limitations, most of this evaluation focuses on

potential gaps associated with the TC analytes and other chemicals. Chapter 8 examines the relationship between

potential gaps, specific industries, and waste management methods. Chapter 9 discusses the extent to which the

various potential gaps may already be addressed to some extent by existing regulatory systems. Finally, Chapter

11 presents a Summary evaluation of the potential gaps against a number of risk and regulatory criteria.

Exhibit 7-1. Summary of Potential Gaps in the Hazardous Waste Characteristics

Category of Potential Gap Nature of Potential Gap

Potential Gaps in the ICR Ignitability

Characteristics Exclusion of DOT combustible liquids

(Sections 3.2 to 3.4) Exclusion of aqueous flammable liquids

References outdated DOT regulations

No test method for non-liquids

Corrosivity

Exclusion of corrosive non-liquids

pH limits are potentially not protective

pH test methods are not predictive of risk

Corrosion of non-steel materials is not addressed

Solubilization of non-metals is not addressed

Exclusion of irritants and sensitizers

Reactivity

Definition is broad, non-specific

References outdated DOT regulations

No test methods are specified

Potential Gaps Associated With Groundwater Pathway Risks

the TC Analytes (Sections 3.5 DAF values potentially not protective

and 3.6)
Exhibit 7-1. Summary of Potential Gaps in the Hazardous Waste Characteristics (continued)

Category of Potential Gap Nature of Potential Gap

Page 7-3

Potential Gaps Associated With Ecological Risks Not Addressed

the TC Analytes (Sections 3.5 Potent ecological toxicants

and 3.6) (continued) Persistent/bioaccumulative pesticides

Non-Groundwater Pathways Not Addressed

Inhalation (volatile organics)

Surface water pathway

Indirect/food chain (volatile, persistent, and bioaccumulative

chemicals)

TCLP Limitations

May not accurately predict leachate concentration or risks for certain

wastes and units

Potential Gaps Associated with Major Constituents/Properties of Non-Hazardous Industrial Wastes Not

Known and Possible ConstituentsAddressed

of Non-hazardous Industrial Metals/inorganics

Waste other than TC Analytes -- groundwater pathway

(Chapter 4) Volatile chlorinated organics

-- groundwater and inhalation pathway exposures

Volatile hydrocarbons

-- groundwater and inhalation pathways

Other volatile organics

-- groundwater and inhalation pathways

Pesticides and related compounds

-- inhalation and indirect food chain pathways

Phthalate esters

-- indirect pathways

Phenolic compounds

-- groundwater and indirect pathways

Polycyclic aromatic hydrocarbons

-- indirect pathway exposures

Other semivolatile organic compounds

-- all pathways

Generation of LNAPLs and DNAPLs

Facilitated transport of organic chemicals

Long-lasting and difficult to remediate
Exhibit 7-1. Summary of Potential Gaps in the Hazardous Waste Characteristics (continued)

Category of Potential Gap Nature of Potential Gap

Page 7-4

Potential Gaps Associated with Natural Resource Damages

Natural Resource Damages and Groundwater resource damage without health risks

Large-Scale Environmental Odors

Problems (Chapter 5)

Large-scale Environmental Problems

Air deposition to the Great Waters

Airborne particulates

Global climate change

Potential damage from endocrine disruptors

Red tides

Stratospheric ozone depletion

Tropospheric ozone and photochemical pollution

Water pollution

Potential Gaps Associated with State Expansion of TC

State Expansion of TC and Additional TC constituents

Listings (Chapter 6) More stringent regulatory levels

Alternative test methods

Use of acute oral, dermal, inhalation, and aquatic LD50 or LC50 criteria

applied to representative samples of waste

State Only Listings

State Restrictions on Federal Exemptions
Page 7-5

CHAPTER 7. SUMMARY OF POTENTIAL GAPS ......................................... 7-1

7.1 Organization of the Analysis of Potential Gaps ....................................... 7-1

7.2 Summary of Potential Gaps ....................................................... 7-2
Page 7-6

Exhibit 7-1. Summary of Potential Gaps in the Hazardous Waste Characteristics ................... 7-2
Page 8-1

CHAPTER 8. POTENTIAL GAPS AS FUNCTION OF

INDUSTRY AND WASTE MANAGEMENT METHODS

This Chapter evaluates the significance of potential gaps by linking the known and possible non-hazardous

industrial waste constituents to specific industries and management practices. It is organized as follows:

Section 8.1 describes the primary data sources used in this chapter and their major

limitations;

Section 8.2 discusses the amount of non-hazardous industrial wastes generated by various

industries and the constituents found in their wastes; and

Section 8.3 reviews the methods of managing non-hazardous industrial wastes and the associated

risks to human health and the environment.

8.1 Data Sources and Major Limitations

Over the past 15 years, EPA has made several substantial efforts to gather information on the types and

amounts of non-hazardous industrial wastes generated by specific industries and the management methods used for

specific wastes. Despite these efforts, significant gaps, inconsistencies, and other limitations remain in the

available information. Considerably fewer data are available on non-hazardous industrial wastes than on

hazardous wastes, in part, because of the limited federal role in regulating non-hazardous industrial wastes and

the lack of widespread reporting requirements.

The major sources of data on non-hazardous industrial waste generation and management are as follows:

Industrial Studies Database (ISDB). EPA has maintained the ISDB since 1982. The

database contains information on waste generation, management, and point-of-generation

constituent concentrations for 16 industries. The sources of the information include

RCRA Section 3007 questionnaires, plant visit reports, sampling and analysis site visit

reports, engineering analysis reports, and data collected for hazardous waste listing

decisions.

The Industrial Subtitle D Telephone Screening Survey. This survey was conducted between

November 1986 and April 1987. Over 18,000 facilities in 17 industry sectors were

questioned about the quantities and types of non-hazardous industrial wastes generated

and managed on-site in 1985, the number and design of on-site management units, and the

amounts of such waste managed in on-site landfills, surface impoundments, waste piles,

and land application units.

National Survey of Treatment, Storage, Disposal, and Recycling Facilities (TSDR

Survey). The TSDR Survey was conducted in 1986 to gather information on waste

generation and management practices for 1986 and any projected changes in waste

management capacity prior to 1992. The Survey questioned approximately 2,500

facilities that manage hazardous waste on-site, including the 2,400 RCRA-permitted or

interim status treatment, disposal, or recycling facilities, and approximately 100 of

the 700 storage facilities. The Survey addressed both hazardous and non-hazardous waste

management at these hazardous waste management facilities. This data source provided
 Systems Applications International Corporation, August 8, 1992, draft. 1

 U.S. Environmental Protection Agency, Office of Solid Waste and Emergency Response, October 1988. 2

Page 8-2

information related to non-hazardous industrial waste management practices and waste

generation by industry groups.

Background documents for recent Agency listings decisions. Reports prepared for the

Agency's proposed decision not to list certain dyes and pigments wastestreams as

hazardous and the proposed decision not to list certain solvent wastestreams as

hazardous. The document identifies the industries responsible for these wastestreams.

In addition, this Chapter uses data from the 1992 Toxic Release Inventory (TRI) on the amount of certain toxic

substances released to land or injected underground by various industries. This data source is discussed in

Section 8.2.4. At the time this Study was prepared, facility-specific data from the 1994 TRI were not available. 

Therefore, 1992 TRI data were used in this chapter. While the use of 1992 instead of more recent TRI data will not

significantly affect the analysis, it will limit the results to a smaller set of chemicals and will not reflect

recent pollution prevention progress.

The first three data sources have the disadvantage of being relatively old. They reflect non-hazardous

industrial waste generation and management practices prevalent a decade or more ago. Since then, patterns of

waste generation and management are likely to have changed in some significant ways in response to the

implementation of RCRA hazardous waste regulations and other federal and state programs. In addition, the ISDB is

rather limited in the number of facilities surveyed in each industry sector, particularly with regard to organic

analytes. The ISDB and Telephone Screening Survey also address only certain industries.

The data sources are not entirely consistent. For example, the estimates of non-hazardous industrial

waste generation for similarly defined industry groups often differ substantially among the sources. These

inconsistencies arise, in part, from the use of different data collection and summarization methods. In the

analyses discussed below, the Agency has used what it considers to be the most reliable and complete data

concerning waste generation and management from these sources.

EPA has previously analyzed the data from the first three data sources to investigate various aspects of

non-hazardous industrial waste generation and management practices. Most of the data presented below come from

two of these studies, the "Industrial D Industry Profiles" and the 1988 "Report to Congress: Solid Waste Disposal 1

in the United States." The former document summarizes non-hazardous industrial waste generation and management 2

practices in 25 industry sectors, while the latter source focuses on the land disposal of all non-hazardous solid

waste covered by the RCRA Subtitle D criteria.
 Ibid., p.2. This volume may include some special wastes, such as in the primary metals or electrical power generation 3

industries.

Page 8-3

8.2 Potential Gaps as a Function of Industry/Waste Source

This section discusses non-hazardous industrial waste generation by various industries as follows:

Section 8.2.1 reviews available data on the volume of such waste generated by specific

industries or industry groups;

Section 8.2.2 compares these data with the industries responsible for the releases documented in

Chapter 2;

Section 8.2.3 identifies the industries responsible for generating non-hazardous industrial wastes

containing constituents with the highest risk of adverse human health effects; and

Section 8.2.4 identifies the industries with facilities reporting TRI releases to land and underground

injection of known or possible non-hazardous industrial waste constituents.

8.2.1 Non-Hazardous Industrial Waste Generation by Industry

In 1988, the Agency estimated that approximately 7.6 billion tons of non-hazardous industrial waste was

generated and managed on-site annually in the United States.3 Approximately 68 percent of this waste came from

four major industry groups:

Paper and allied products (SIC 26): 2.25 billion tons (29.6 percent);

Chemicals and allied products (SICs 2812-2819, 2821, 2824, 2851, 2891, 2865, 2869, and

287): 1.39 billion tons (18.2 percent);

Primary metals industries (SICs 3312-3321 and 3331-3399): 1.37 billion tons (18.0

percent); and

Petroleum refining and related industries (SIC 29): 168 million tons (2.2 percent).

On the basis of the amounts of waste generated and risk-based screening of waste constituents, the Office

of Solid Waste identified these four industry groups as "priority industries" for possible further regulation. 

Other industries that generate more non-hazardous industrial wastes than petroleum refining were not identified

as priority industries on the basis of risk-based screening of waste constituents. Exhibit 8-1 summarizes the

estimates of non-hazardous industrial waste generation for the four priority industries and corresponding

industry sectors and for other relatively high volume industries and sectors.
Page 8-4

Exhibit 8-1

Estimated Generation of Non-Hazardous Industrial Waste by Major Industry Group

Industry Group SIC (thousand tons/yr.)

Total On-site Generation

Paper and Allied Products 26 2,251,700

Primary Metals Industry 33 1,367,611 a

 Primary Iron and Steel 332 1,300,541

 Primary Non-ferrous Metals 333 67,070

Chemicals and Allied Products 28 1,324,722 b

 Industrial Inorganic Chemicals 281 919,725

 Fertilizer and Agricultural Chemicals 287 165,623

 Plastics and Resins Manufacturing 282 180,510

 Industrial Organic Chemicals 286 58,864

Electric, Gas, and Sanitary Services 49 1,151,123 c

 Electric Power Generation 4911 1,092,277

 Water Treatment 4941 58,846

Stone, Clay, Glass, and Concrete 32 621,974

Food and Kindred Products 20 373,517

Textile Manufacturing 22 253,780

Petroleum Refining 29 168,632

Rubber and Miscellaneous Products 30 24,198

Transportation Equipment 37 12,669

Leather and Leather Products 31 3,234

Source: U.S. Environmental Protection Agency, "Report to Congress: Solid Waste Disposal in the United States,"

Volume II, Table 3-5, October 1988.

 The Primary Metals Industry includes only SICs 332 (Primary Iron and Steel) and 333 (Primary Non-ferrous a

Metals).

 Chemicals and Allied Product Industry includes only SICs 281 (Industrial Inorganic Chemicals), 282 (Plastics b

and Resins Manufacturing), 286 (Industrial Organic Chemicals), and 287 (Fertilizer and Agricultural Chemicals).

 Electric, Gas, and Sanitary Services Industry includes only SICs 4911 (Electric Power Generation) and 4941 c

(Water Treatment).
 Health-based or ecologically-based standards included Primary MCLs, MCLGs, and state standards established to protect health

4

or the environment. Non-health-based or non-ecologically-based standards are those set to preserve groundwater usability or

aesthetics, such as Secondary MCLs or standards for which any health or ecological bases were not explained.

 

5

 EPA lacks information on the regulatory standards that were exceeded for all releases from California and for two releases from

other states. All releases described in this Study, however, were documented to have exceeded one or more applicable federal, state,

or local regulatory standards.

Page 8-5

The listing documents for solvent wastes and wastes from the dye and pigment industries are another source

of information on non-hazardous industrial waste. All of the information related to waste volumes and

constituents concentrations for the dye and pigment industries, however, was claimed proprietary by the

submitters and, therefore, could not be included in this Study. EPA recently identified non-hazardous industrial

solvents in developing a recent proposed rulemaking. The amounts of solvent wastes have not been broken down by

industry and, therefore, could not be included in Exhibit 8-1.

8.2.2 Industries Responsible for Documented Non-Hazardous Industrial Waste Releases

The environmental release descriptions discussed in Chapter 2 provide additional evidence about the

industries (and waste management practices) associated with potential gaps in the characteristics. Exhibit 8-2

tabulates, by industry, the frequency of documented releases and their exceedence of health-based or

ecologically-based regulatory standards. As shown in this exhibit, some of the industries that show up frequently

in the release descriptions are among the high-volume industries identified above. The most frequently occurring

industry group in the release descriptions is electric, gas, and sanitary services (SIC 49) with all of those

release descriptions originating in the refuse systems sector (SIC 4953). This industry sector includes

commercial waste management facilities. As noted in Chapter 2, most of these commercial non-hazardous industrial

waste management units are located in California, where considerable monitoring data were available. From these

data, EPA could not determine the industries that generate the wastes managed by these commercial facilities.

The next three industry groups with the most documented releases are the paper and allied products (27

releases), chemicals and allied products (11 releases), and food and kindred products (10 releases). These

industry groups also are among the largest generators of non-hazardous industrial waste. The primary metals

industry, another high-volume group, also has a moderate number of documented releases; they account for 6 of the

112 total releases documented in Chapter 2.

Exhibit 8-2 also shows the numbers of documented releases at which the maximum detected concentrations of

constituents exceeded health-based or ecologically-based standards. All but six of the 101 releases with data on 4

the standards exceeded had exceedences of health- or ecologically-based standards. These six releases exceeded 5

secondary maximum contaminant levels (SMCLs) only. Sixty-five of these releases also violated other standards.

Exhibit 8-3 shows the total numbers of times particular chemicals were found in the release descriptions

for various industry sectors. (The totals are the sums of the number of individual chemicals detected at each

site, counting all chemicals for each site, even if a chemical is detected at more than one site. For example, the

total detections at two sites having 10 chemicals each, 3 of which are the same, is 20, not 17.) In addition, the

exhibit shows the numbers of times such
Page 8-6

Exhibit 8-2

Chemicals Exceeding Health-Based and Non-Health-Based Regulatory Levels

in the Release Descriptions for Non-Hazardous Waste Management

Industry Group (SIC) Total Exceedences Exceedences Exceedences

Number of Release Descriptions

a

With Both Health/

Ecological and With Only With Only NonNon-Health/Non- Health/ Health/NonEcological Ecological Ecological

Electric, Gas, and Sanitary Services (49) 35 11 11 4

Paper and Allied Products (26) 27 22 4 1

Chemicals and Allied Products (28) 11 8 3 0

Food and Kindred Products (20) 10 6 3 0

Primary Metal Industries (33) 6 2 4 0

Nonmetallic Minerals, Except Fuels (14) 4 4 0 0

Petroleum Refining (29) 4 3 1 0

Fabricated Metal Products (34) 3 0 2 1

Transportation Equipment (37) 3 3 0 0

Agricultural Production--Livestock (02) 2 2 0 0

Electronic and Other Electronic Equipment (36) 2 1 0 0

Stone, Clay, and Glass Products (32) 2 2 0 0

Apparel and Other Textile Products (23) 1 1 0 0

Industrial Machinery and Equipment (35) 1 0 1 0

Instruments and Related Products (38) 1 0 1 0

Total 112 65 30 6

 The total number of release descriptions in column 2 may not equal the sum of the release descriptions in columns 3, 4, and a

5. Column 2 includes all release descriptions for chemicals that were documented to have exceeded at least one applicable

federal, state, or local regulatory standard. Columns 3, 4, and 5 include only those release descriptions in Column 2 for which

supporting data indicate which regulatory standards were exceeded. Information was not available on the regulatory standards

that were exceeded for all releases from California and for two releases from other states.
Page 8-7

Exhibit 8-3

Numbers of Chemical Detections and Frequencies of Regulatory Exceedences in Release Descriptions

Industry Group (SIC) Descriptions Total Mean Per Release Total Release Total Release

Number of

Release Mean Per Mean Per

Chemical Detections Regulatory Exceedences Based Exceedences

Health- or EcologicallyElectric, Gas, and Sanitary Services (49) 35 350 10 91 3 58 2

Paper and Allied Products (26) 27 340 13 148 5 85 3

Chemicals and Allied Products (28) 11 250 23 97 9 73 7

Food and Kindred Products (20) 10 72 7 22 2 13 1

Primary Metal Industries (33) 6 58 10 27 5 24 4

Nonmetallic Minerals, Except Fuels (14) 4 91 23 49 12 34 9

Petroleum Refining (29) 4 40 10 16 4 8 2

Fabricated Metal Products (34) 3 12 4 7 2 5 2

Transportation Equipment (37) 3 48 16 19 6 14 5

Agricultural Production--Livestock (02) 2 18 9 8 4 5 3

Electronic and Other Electronic Equipment (36) 2 16 8 4 2 1 0

Stone, Clay, and Glass Products (32) 2 33 17 14 7 10 5

Apparel and Other Textile Products (23) 1 3 3 3 3 2 2

Industrial Machinery and Equipment (35) 1 7 7 3 3 3 3

Instruments and Related Products (38) 1 2 2 1 1 1 1

Total 112 1,340 --- 509 --- 336 ---
 These are chemicals that were identified as having Cancer Slope Factors or Unit Risks in IRIS or HEAST. 6

Page 8-8

chemicals were detected above regulatory levels, and the proportions of chemicals found above health-based or

ecologically-based standards. The 3 industries with the most releases, electric, gas, and sanitary services (35

releases), paper and allied products (27 releases), and chemicals and allied products (11 releases), also had the

highest numbers of chemical detections (350, 340, and 250, respectively). The average number of chemicals

detected per facility varies substantially across industries. For example, the 3 industries noted above had means

of 10, 13, and 23 chemicals detected per release, respectively. The average number of regulatory and health- or

ecologically-based exceedences per release also varies greatly across industries. For example, the electric,

gas, and sanitary services industry averages only 3 regulatory and 2 health- or ecologically-based exceedences for

every 10 chemical detections. In contrast, the chemical industry averages 9 regulatory and 7 health- or

ecologically-based exceedences for every 23 chemical detections.

8.2.3 Occurrence of High-Hazard Industrial Waste Constituents by Industry

Another indicator of the potential severity of hazards associated with releases from non-hazardous

industrial waste management in various industries is the frequency of occurrence of waste constituents with the

highest risk to humans. Exhibit 8-4 identifies the chemicals that appeared most frequently in the release

descriptions, the number of total appearances, and the number of times the chemical was present in groundwater

above regulatory or other health-based levels based on 10 cancer risks or a hazard quotient greater than 1.0. As -5

noted in Section 5.1, many of the most frequently occurring chemicals do not have health-based or ecologicallybased standards, but may have SMCLs or other regulatory levels. Among these are the three most common constituents

found in the release descriptions: iron, chloride, and sodium, as well as manganese, zinc, calcium, magnesium,

potassium, copper, aluminum, and silver.

A substantial number of potentially toxic chemicals were detected in the release descriptions. For

example, 11 of the 52 most frequently detected chemicals are known or suspect carcinogens by ingestion or

inhalation. Only one of the most frequently detected chemicals (phosphorous) is identified as having a low RfD, 6

although several other chemicals on the list are generally considered toxic, including lead, mercury, cadmium,

arsenic, and chromium. Seven of the most frequently detected chemicals are chlorinated volatile organics, with

trichlorethylene, occurring most often (17 times). While all of the inorganic analytes appearing on the list are

persistent, none of the most frequently occurring organic chemicals were identified as persistent in Chapter 4. 

In fact, none of the persistent bioaccumulative chlorinated pesticides identified as posing potentially high

risks are seen in the release descriptions more than three times and most were seen in only one release

description. 

Exhibit 8-5 shows the number of occurrences and the number of regulatory, health-based, or ecologicallybased exceedences for the constituents detected most frequently in the release descriptions for each industry

group. For each group, the 15 most frequently detected chemicals or all detected chemicals are shown, whichever is

smaller. In almost all industry groups, inorganic chemicals are found more often than organics. This finding may

be due, in part, to a lack of analytical data for organic chemicals in some industries. Volatile organic chemicals

are rarely found among the most frequently detected chemicals, with a few exceptions. Iron, manganese, and

sulfate were among the most frequently found chemicals in the electric, gas, and sanitary services release

descriptions, and volatile organics represent the bulk of the most frequently detected chemicals for the

electronic and other electronic equipment industry and the petroleum refining industry. The relative scarcity of
Page 8-9

Exhibit 8-4

Most Frequently Occurring Constituents in the Release Descriptions

Constituent Descriptions Regulatory Levels or HBLs

Number of Occurrences in Release Number of Occurrences Above

a

TC Constituents

Lead 37 22

Chromium 36 21

Arsenic 29 24

Barium 28 28

Cadmium 28 28

Benzene 23 16

Mercury 19 6

Selenium 18 18

Trichloroethylene 17 8

Vinyl chloride 13 6

Silver 12 12

Chlorobenzene 9 9

Tetrachloroethylene 9 9

Chloroform 8 8

1,4-Dichlorobenzene 5 0

SMCL Constituents

Iron 54 49

Chloride 52 32

Manganese 39 39

Zinc 33 33

Copper 17 17

Aluminum (fume or dust) 12 12

Fluorides 12 4

Other Constituents

Sodium 40 8

Nitrates 33 30

Magnesium 32 3

Calcium 30 0

Potassium 21 0

Other Constituents (continued)
Exhibit 8-4 (continued)

Most Frequently Occurring Constituents in the Release Descriptions

Constituent Descriptions Regulatory Levels or HBLs

Number of Occurrences in Release Number of Occurrences Above

a

Page 8-10

Toluene 20 20

Phenol 18 18

Ammonia 16 11

Calcium carbonate 15 0

Nickel 14 4

Dichloromethane 12 12

Nitrite 11 9

Ethylidene dichloride 10 10

Xylene (mixed isomers) 10 10

Acetone 9 9

Nitrogen 8 0

Beryllium 7 7

cis-1,2-Dichloroethylene 7 7

Ethylbenzene 7 7

Vanadium (fume or dust) 7 6

1,2-Dichloroethylene 6 6

Boron and compounds 6 3

Chloromethane 6 0

Cyanides 6 6

Phosphorus 6 1

1,2-Dichlorobenzene 5 5

Antimony 5 5

Carbon disulfide 5 5

Cobalt 5 0

Naphthalene 5 3

 Regulatory levels include MCLs, SMCLs, AWQCs, or other state health- or ecologically-based standards. HBLs are drinking a

water concentrations corresponding cancer risk of 10 or Hazard Quotient of 1.0 for an adult, using IRIS or HEAST toxicity -5

criteria.
Page 8-11

Exhibit 8-5

Occurrence of Waste Constituents by Industry Group

Industry Group (SIC) Constituent Descriptions based Levels

Number of Regulatory,

Occurrences in Health- or

Release EcologicallyNumber of

Occurrences Above

Paper and Allied Products (26) pH 22 12 *

Chloride 21 13 *

Iron 21 21 *

Sulfate 20 12 *

Sodium 15 2

Calcium carbonate 12 0

Calcium 11 0

Magnesium 11 2

Zinc 11 11 *

TDS 10 7

*

Chromium 9 5

Manganese 9 9

*

Arsenic 8 7

Barium 7 7

Cadmium 7 7

Refuse Services (495) pH 19 3

*

Iron 14 10 *

Manganese 13 13 *

Sulfate 13 4

*

Lead 12 4

Chloride 11 7

*

Magnesium 10 1

Nitrate 10 7

TDS 10 1

*

Trichloroethylene 10 3

Benzene 9 3

Calcium 9 0

Chromium 9 4

Sodium 9 1

Vinyl Chloride 9 3

Chemicals and Allied Products (28) Benzene 7 6
Exhibit 8-5 (continued)

Occurrence of Waste Constituents by Industry Group

Industry Group (SIC) Constituent Descriptions based Levels

Number of Regulatory,

Occurrences in Health- or

Release EcologicallyNumber of

Occurrences Above

Page 8-12

Chromium 7 4

Iron 7 6

*

Lead 6 4

Manganese 6 6

*

Sulfate 6 4

*

TDS 6 4

*

Zinc 6 6

*

Arsenic 5 5

Chloride 5 1

*

Fluoride 5 1

*

Total Organic Carbon 5 1

Acetone 4 4

Barium 4 4

Cadmium 4 4

Nonmetallic Minerals, Except Fuels (14) Arsenic 4 2

Iron 4 4

*

Lead 4 4

Manganese 4 4

*

pH 4 2

*

Cadmium 3 3

Chloride 3 3

*

Copper 3 3

*

Nickel 3 1

Potassium 3 0

Sodium 3 0

Sulfate 3 3

*

Zinc 3 3

*

Aluminum 2 2

Barium 2 2

Food and Kindred Products (20) Nitrite 6 4

Nitrate 5 5
Exhibit 8-5 (continued)

Occurrence of Waste Constituents by Industry Group

Industry Group (SIC) Constituent Descriptions based Levels

Number of Regulatory,

Occurrences in Health- or

Release EcologicallyNumber of

Occurrences Above

Page 8-13

Nitrogen 5 0

pH 4 0

*

TDS 4 3

*

Total filterable residue 4 0

Calcium 3 0

Chloride 3 2

*

Magnesium 3 0

Sodium 3 2

Sulfate 3 2

*

Ammonia 2 1

Bicarbonate 2 0

Conductivity 2 0

Copper 2 2

*

Primary Metal Industries (33) Lead 4 4

Chromium 3 3

Aluminum 2 2

*

Arsenic 2 2

Barium 2 2

Cadmium 2 2

Chloride 2 2

*

Conductivity 2 0

Mercury 2 0

Nickel 2 2

Zinc 2 2

*

2,4,6-Trichlorophenol 1 0

2,4-Dichlorophenol 1 1

2,4-Dimethylphenol 1 1

2,4-Dinitrophenol 1 1

Petroleum Refining (29) Chloride 3 2

*

Conductivity 2 1

Di-n-butylphthalate 2 1
Exhibit 8-5 (continued)

Occurrence of Waste Constituents by Industry Group

Industry Group (SIC) Constituent Descriptions based Levels

Number of Regulatory,

Occurrences in Health- or

Release EcologicallyNumber of

Occurrences Above

Page 8-14

Naphthalene 2 1

pH 2 1

*

Sulfate 2 2

*

TDS 2 2

*

1,2-Dichloroethane 1 1

2-Methylnaphthalene 1 0

Acenaphthene 1 1

Acetone 1 1

Barium 1 1

Benzene 1 1

Carbon disulfide 1 1

Chlorobenzene 1 1

Agricultural Production--Livestock (02) Ammonia 2 0

Nitrate 2 2

TDS 2 2

*

Bicarbonate 1 0

Calcium 1 0

Chemical Oxygen Demand 1 0

Chlorine 1 1

*

Iron 1 1

*

Magnesium 1 0

Nitrite 1 1

Nitrogen 1 0

pH 1 0

*

Phosphorus 1 0

Sodium 1 1

Toluene 1 1

Transportation Equipment (37) Phenol 3 3

Barium 2 2

Chromium 2 1

Total Organic Carbon 2 1
Exhibit 8-5 (continued)

Occurrence of Waste Constituents by Industry Group

Industry Group (SIC) Constituent Descriptions based Levels

Number of Regulatory,

Occurrences in Health- or

Release EcologicallyNumber of

Occurrences Above

Page 8-15

1,1-Dichloroethane 1 1

2,4-Dimethylphenol 1 0

Aluminum 1 1

*

Ammonia 1 1

Antimony 1 1

Arsenic 1 1

BEHP 1 1

Benzene 1 1

Beryllium 1 1

Cadmium 1 1

Calcium 1 0

Electronic and Other Electronic Equipment (36) 1,1-Dichloroethane 1 1

Carbon tetrachloride 1 1

Chloride 1 1

*

Chloroform 1 1

Iron 1 1

*

Manganese 1 1

*

Methylene chloride 1 1

pH 1 0

*

Phenolics 1 0

Sodium 1 0

Sulfate 1 1

*

Tetrachloroethylene 1 1

Toluene 1 1

Total Organic Carbon 1 0

Total Organic Halogens 1 0

Stone, Clay, and Glass Products (32) Ammonia 1 1

Arsenic 1 1

Barium 1 1

Benzene 1 1

Beryllium 1 1
Exhibit 8-5 (continued)

Occurrence of Waste Constituents by Industry Group

Industry Group (SIC) Constituent Descriptions based Levels

Number of Regulatory,

Occurrences in Health- or

Release EcologicallyNumber of

Occurrences Above

Page 8-16

Cadmium 1 1

Calcium 1 0

Carbon disulfide 1 1

Chemical Oxygen Demand 1 0

Chloride 1 0

*

Chromium 1 1

Cobalt 1 0

Conductivity 1 0

Copper 1 1

*

Cyanide 1 1

Fabricated Metal Products (34) Chemical Oxygen Demand 1 0

Chloride 1 1

*

Chromium 1 1

cis-1,2-Dichloroethylene 1 1

Lead 1 0

Manganese 1 1

*

Nitrate 1 1

pH 1 1

*

Phenol 1 1

Total Dissolved Solids 1 0

*

Trichloroethylene 1 1

Zinc 1 1

*
Exhibit 8-5 (continued)

Occurrence of Waste Constituents by Industry Group

Industry Group (SIC) Constituent Descriptions based Levels

Number of Regulatory,

Occurrences in Health- or

Release EcologicallyNumber of

Occurrences Above

Page 8-17

Industrial Machinery and Equipment (35) Arsenic 1 0

Cadmium 1 1

Chromium 1 0

Lead 1 1

pH 1 0

*

Phenol 1 1

Zinc 1 1

*

Apparel and Other Textile Products (23) Cadmium 1 1

Nitrate 1 1

Total Organic Carbon 1 1

Instruments and Related Products (38) Grease and Oil 1 0

Phenol 1 1

 Constituents with Secondary Maximum Contaminant Levels. *

organics for some of the industries could be slightly misleading. For example, a large number of volatile organic

chemicals were detected in the release descriptions from the chemicals and allied products industry and petroleum

refining, but each chemical was detected infrequently, so they do not appear in Exhibit 8-5.

The persistent chlorinated pesticides were not among the most frequently detected chemicals, except in

two industries. Pentachlorophenol was detected in a single release description from the primary metals industry. 

Semivolatile organics are likewise not among the most frequently detected analytes in the release descriptions,

but this may be a function of the poor mobility of many of these chemicals in groundwater, rather than their lack of

presence in the wastes. As was the case for the volatile organics, a large number of pesticides and semivolatile

organics were detected in the release descriptions from the chemicals and allied products sector and each such

chemical was found only one or a few times.

The pattern of chemical detections and health-based or ecologically-based exceedences varied widely

among the industry groups, as discussed in Section 8.1.2. As noted previously, the frequency of non-health-based

and non-ecologically-based exceedences is relatively high among some industry groups with the highest number of

total chemicals detected. For example, SMCLs, which are based on aesthetic considerations (e.g., water taste and

odor), exist for 6 of the 15 most commonly detected analytes for the refuse systems sector (SIC 4953) and the paper

and allied products industry (SIC 26), and 7 of the 15 analytes from the chemicals and allied products industry

(SIC 28). Again, this finding may be somewhat misleading because many of the less frequently detected analytes
 Detailed 1994 TRI facility-specific data were not available when this Study was prepared, therefore, 1992 TRI data were used.

7

Page 8-18

from these sectors do have health-based or ecologically-based standards. Furthermore, some constituents with

SMCLs may also pose health and ecological risks. The same pattern applies to stone, clay, and gas products (SIC

32), and food and kindred products (SIC 20). In the food and kindred products industry, the only health-based

exceedences were for nitrates, nitrites, or both. All of the other most frequent exceedences for this industry

group were non-health-based and non-ecologically-based.

8.2.4 Industries Reporting Releases of TC Analytes or Known or Possible Non-Hazardous Industrial Waste

Constituents

Another indication of the potential importance of the various industries with regard to non-hazardous

industrial waste management is provided by data concerning the amounts of chemicals these industries release to

the environment, as reported under the EPCRA TRI requirements. Exhibit 8-6 identifies, by industry, volumes of TC

analytes or known or possible non-hazardous industrial waste constituents that in 1992 were reported released to

land or underground injection in an amount exceeding 1 million pounds. Volumes of waste released to land or 7

underground injection are presented in this Study because they are thought to be the most indicative of the volume

of non-hazardous waste at the facilities. The listed volumes are the mass of individual constituents in waste

streams or other emissions rather than total waste volumes as presented in other exhibits in this chapter. The

volumes may include hazardous, special, and municipal solid waste as well as non-hazardous industrial waste.

The largest volume of constituents reported released via underground injection in 1992 were from the

chemicals and allied products industry, which contributed 99.3 percent of total volume from underground

injection. A significant portion of these constituents may be in hazardous wastewaters. The second and third

largest volumes of TRI constituents come from the petroleum refining and primary metals industries, which

contributed 0.57 and 0.04 percent of total volume from underground injection, respectively. The two constituents

released in the largest volumes to underground injection from the chemicals and allied products industry were

methanol and acetonitrile, with 38 and 29 percent of total volume for that industry, respectively. Methanol was

also released in the highest volume from the petroleum refining industry, comprising 57 percent of the total

constituent volume reported for that industry.

The largest volume of constituents released to land originates from the primary metals industry, which

contributes 74.2 percent of the total volume. Most of that volume (99 percent) is comprised of constituents, such

as zinc, copper, and chromium, that may be present in large volume special wastes. (Further investigation is

needed to determine whether any of these releases involve special or hazardous wastes.) The two chemicals

comprising almost equal proportions released by this industry are zinc and copper, with about 48 percent each. The

second and third largest volumes of constituents were from the petroleum refining and paper and allied products

industries, respectively. Petroleum refining contributed 10.1 percent of total volume and paper and allied

products contributed 8.4 percent of total volume released to land. Naphthalene and xylene, with 43 and 32 percent

of total volume reported released to land, constituted the largest proportion of the constituents from the
Page 8-19

Exhibit 8-6 Non-Hazardous Industrial Waste Constituents Reported Released by Industry
Page 8-20

Exhibit 8-6 Non-Hazardous Industrial Waste Constituents Reported Released by Industry (continued)
Page 8-21

petroleum refining industry. Almost 99 percent of the volume of constituents released to land by the paper and

allied products industry was methanol.

8.3 Potential Gaps as a Function of Management Practices

This section of the Scoping Study reviews the available information related to management practices:

Section 8.3.1 examines the prevalent management practices among the major non-hazardous

industrial waste generating industries;

Section 8.3.2 reviews the evidence regarding environmental releases as a function of

management type for major management technologies;

Section 8.3.3 describes limited data available on the potential hazards associated with use

constituting disposal; and

Section 8.3.4 briefly discusses the potential nature of the hazards associated with less wellcharacterized management practices.

8.3.1 Waste Management Practices by Waste Type and Industry

As noted previously, the data related to non-hazardous industrial waste management practices are quite

limited and may be somewhat outdated. Inconsistencies frequently were found between data from the different

sources. Exhibit 8-7 summarizes the information for the relatively high volume generation industries. Based on

the available information, the vast majority of non-hazardous industrial waste is aqueous and is managed in

surface impoundments before treatment and ultimate discharge under NPDES. The proportion of these wastes going to

surface impoundments in 1985 ranged from 78.6 percent in the food and kindred products industry to 99.7 percent in

the textile manufacturing industry, with a total of 96.5 percent of all wastes managed in this fashion in the 15

industries included in the exhibit. The second most widely used land-based management technology was land

application. Only about 1.3 percent of the waste volume from the 15 industries was managed in this fashion in 1985,

with substantially larger proportions going this route in the organic chemicals industry (3.1 percent), the food

and kindred products industry (20 percent), and water treatment industry (15 percent). Landfills and waste piles

each accounted for about one percent of the total waste managed in the 15 industries.

Exhibit 8-8 estimates the number of active landfills, surface impoundments, land application units, and

waste piles used to manage non-hazardous waste in various industry groups in 1985. At that time, 55 percent of

these land-based units were surface impoundments. This finding indicates that, on average, surface impoundments

handled larger volumes of waste than other management units since they managed a substantially greater percentage

(96 percent) of total on-site non-hazardous industrial waste. In all industries except primary iron and steel and

transportation equipment, surface impoundments were the most common type of management units. Waste piles

constituted 19 percent of the total units. They were the most common type of unit in the primary iron and steel and

transportation equipment industries, were the second most common type in eight industries, and tied for second in

another. Land application units represented 16 percent of all units. Over 70 percent of these units, however,

were in the food and kindred products industry. Landfills represented only 10 percent of all units.
Page 8-22

Exhibit 8-7

Volume of Non-Hazardous Industrial Waste Managed in Land-Based Facilities in 1985

Major Industry Group (SIC)

Treatment or Disposal Method (percentages) Total a

Landfill Impoundment Application Piles (1000 tons/yr.)

Surface Land Waste Tons Managed

Paper and Allied Products (26) 0.30% 99.30% 0.40% 0.07% 2,251,700 

Primary Metals Industry (33) 0.39 98.5 0.04 1.1 1,367,611 b

 Primary Iron and Steel (332) 0.3 99.2 <0.01 0.5 1,300,541 

 Primary Non-ferrous Metals (333) 2.1 84.3 0.6 13 67,070 

Chemicals and Allied Products (28) 0.74 95.3 0.21 3.7 1,324,722 c

 Industrial Inorganic Chemicals (281) 0.4 95.1 0.01 4.5 919,725 

 Plastics and Resins Manufacturing (282) 0.05 98.2 0.02 1.7 180,510 

 Fertilizer and Agricultural Chemicals (287) 3.5 93.1 0.5 2.9 165,623 

 Industrial Organic Chemicals (286) 0.4 96.3 3.1 0.08 58,864 

Electric, Gas, and Sanitary Services (49) 4.7 94.5 0.78 0.08 1,151,123 d

 Electric Power Generation (4911) 4.9 95 0.03 0.08 1,092,277 

 Water Treatment (4941) 0.3 84.5 15 0.1 58,846 

Stone, Clay, Glass, and Concrete (32) 1.2 97.3 <0.01 1.5 621,974 

Food and Kindred Products (20) 1 78.6 20 0.1 373,517 

Textile Manufacturing (22) 0.03 99.7 0.3 <0.01 253,780 

Petroleum Refining (29) 0.2 99.6 0.2 0.05 168,632 

Rubber and Misc. Products (30) 2.2 97.4 0.2 0.2 24,198 

Transportation Equipment (37) 1.4 93.1 <0.01 4.6 12,669 

Leather and Leather Products (31) 0.3 99.4 0 0.3 3,234 

Total 1.10% 96.50% 1.30% 1% 7,621,147 

Source: U.S. Environmental Protection Agency, "Report to Congress: Solid Waste Disposal in the United States," Volume

II, Table 3-5, October 1988.

 The entries in each column may not add to their respective totals because of rounding. a

 The Primary Metals Industry includes only SICs 332 (Primary Iron and Steel) and 333 (Primary Non-ferrous Metals). b

 Chemicals and Allied Products includes only SICs 281 (Industrial Inorganic Chemicals), 282 (Plastics and Resins c

Manufacturing), 286 (Industrial Organic Chemicals), and 287 (Fertilizer and Agricultural Chemicals).

 Electric, Gas, and Sanitary Services includes only 4911 (Electric Power Generation) and 4941 (Water Treatment). d
Page 8-23

Exhibit 8-8

Active Non-Hazardous Industrial Waste Management Units in 1985 by Major Industry Group

Major Industry Group (SIC) Landfill Impoundment Application Piles Total

Number of Treatment or Disposal Units

Surface Land Waste

Food and Kindred Products (20) 194 4,166 3,128 540 8,028 

Stone, Clay, Glass, and Concrete Products 1,257 3,152 309 2,528 7,246 

(32)

Paper and Allied Products (26) 259 918 139 232 1,548 

Electric Power Generation (4911) 155 1,220 43 110 1,528 

Industrial Inorganic Chemicals 120 1,039 24 98 1,281 

(2812-2819)

Petroleum Refining (29) 61 915 114 158 1,248 

Primary Iron and Steel (3312-3321) 201 383 76 464 1,124 

Water Treatment (4941) 121 659 147 48 975 

Textile Manufacturing (22) 28 741 72 103 944 

Primary Non-ferrous Metals (3330-3399) 111 448 9 312 880 

Transportation Equipment (37) 63 287 11 362 723 

Fertilizer and Agricultural Chemicals 31 274 160 50 515 

(2873-2879)

Rubber and Miscellaneous Products (30) 77 176 16 123 392 

Industrial Organic Chemicals (286) 17 262 27 79 385 

Plastics and Resins Manufacturing (2821) 32 292 17 32 373 

Selected Chemicals and Allied Products 21 219 17 41 298 

(28, except sectors otherwise noted)

Leather and Leather Products (31) 9 102 0 54 165 

Total 2,757 15,253 4,308 5,335 27,653 a

Source: Report to Congress, "Solid Waste Disposal in the United States," Volume II, EPA, Office of Solid Waste and

Emergency Response, October 1988.

 The entries in each column may not add to their respective totals because of rounding. a
Page 8-24

Surface impoundments, land application, landfills, and waste piles are clearly not the only management

technologies that can be used for non-hazardous industrial wastes. The totals in Exhibit 8-7 do not reflect all of

the possible options for waste management. Exhibit 8-9 provides data from the Industrial D Industry Profiles

discussed in Section 8.1 relating to non-hazardous industrial waste management practices in some industries

occurring most frequently in the release descriptions. Most of these data are from the 1987 TSDR, and some are from

the ISDB. Waste management practices summarized in this source are substantially different from those shown

previously. The data are more detailed, and information is given for additional management methods, including

container/tank storage, wastewater treatment systems, underground injection, recycle/reuse, and incineration.

The TSDR/ISDB data identify wastewater treatment systems (WWT and tank systems) as the dominant

management methods for most industries, instead of surface impoundments. This difference may be partially due to

the characterization of management units in the two surveys. Many of the units identified as “impoundments” in the

TSS may have been identified as “WWT units” in the TSDR or ISDB. Also, the populations of facilities and wastes

covered in the two surveys are different. For example, the TSDR Survey covered facilities in a wide range of

industries, but only if they managed hazardous waste. The ISDB, on the other hand, covered a broader range of

facilities, but only if they were in certain industry groups. In any event, the two sources generally agree that

land-based treatment for aqueous wastes is the dominant management method for non-hazardous industrial wastes.

Land application, landfills, and waste piles show up as relatively minor management technologies, by

volume, in the TSDR/ISDB data, consistent with the TSS data. Underground injection is also a minor but not

insignificant management technology, accounting for up to approximately three percent of total waste management

in the industries where it is most widely used. Some non-hazardous industrial wastes from all of the industries

evaluated are recycled or reused (up to about 1.5 percent). Incineration also accounted for less than one percent

of all non-hazardous industrial wastes managed in the various industries. The only waste management technology

identified as being important for any industry other than those mentioned is “other processes/methods,” which

accounted for almost 50 percent of the wastes managed from the stone, clay, glass, and concrete industry. The

process used to manage these wastes was not indicated, but it may include use in roadbed or fill.

8.3.2 Management Practices Seen in the Release Descriptions

The release descriptions for non-hazardous industrial waste management contain information about the

types of management units at which releases to the environment have occurred. This source provides some direct

evidence as to which types of management practices have the greatest potential for causing releases to the

environment. Its major limitations, however, are that it covers only facilities for which data were readily

available, namely regulated units, and that some of releases are relatively old.
Page 8-25

Exhibit 8-9

Non-Hazardous Industrial Waste Management by Industry

and Waste Type from TSDR and ISDB

Industry Group (SIC) Type(s) Management Type(s) metric tons)

Major Waste (thousand

a,b

Total Amount

Chemicals and Allied Aqueous Liquid WWT & Tank Systems 79,669 

Products (280, 282 (except Organic Liquid

2821), 285, 288, 289 (except

2891, 2892, 2893))

c

Surface Impoundments 2,029 c

Underground Injection 236 c

Incineration 43 c

Landfill 14 c

Other Processes/Methods 8 c

Recycle/Reuse 4 c

Land Application <1 b

Industrial Inorganic Aqueous Liquid WWT & Tank Systems 25,421 

Chemicals (281) Solid Residue

Gas

Sludge/Slurry

c

Underground Injection 958 c

Recycle/Reuse 752 b

Other Processes/Methods 395 b

Waste Pile Storage 356 b

Surface Impoundments 263 b

Landfill 43 b

Incineration 2 c

Plastics and Resins (2821) Aqueous Liquid WWT & Tank Systems 68,414 c

Surface Impoundments 45,842 c

Underground Injection 421 b

Landfill 132 b

Recycle/Reuse 73 b

Land Application 41 b

Incineration 25 b

Waste Pile Storage 5 b

Other Processes/Methods 3 b

Container/Tank Storage <1 b
Exhibit 8-9 (continued)

Non-Hazardous Industrial Waste Management by Industry

and Waste Type from TSDR and ISDB

Industry Group (SIC) Type(s) Management Type(s) metric tons)

Major Waste (thousand

a,b

Total Amount

Page 8-26

Drug and Medical Products Aqueous Liquid WWT & Tank Systems 197,143 

(283)

c

Recycle/Reuse 1,818 c

Surface Impoundments 193 c

Underground Injection 126 c

Incineration 18 c

Landfill <1 c

Industrial Organic Chemicals Aqueous Liquid WWT & Tank Systems 182,642 

(268) Gas

Organic Liquid

c

Surface Impoundments 78,193 c

Recycle/Reuse 3,867 b

Other Processes/Methods 3,705 b

Underground Injection 3,296 b

Incineration 1,667 b

Landfill 1,406 b

Land Application 225 b

Other Processes/Methods 33 c

Container/Tank Storage 7 b

Waste Pile Storage 3 c

Agricultural Chemicals (287) Aqueous Liquid WWT & Tank Systems 110,869 c

Surface Impoundments 664 c

Underground Injection 462 b

Other Processes/Methods 122 c

Incineration 52 b

Landfill 37 b

Land Application 29 b

Container/Tank Storage 20 b

Recycle/Reuse 13 b

Waste Pile Storage 2 b
Exhibit 8-9 (continued)

Non-Hazardous Industrial Waste Management by Industry

and Waste Type from TSDR and ISDB

Industry Group (SIC) Type(s) Management Type(s) metric tons)

Major Waste (thousand

a,b

Total Amount

Page 8-27

Products of Petroleum and Aqueous Liquid WWT & Tank Systems 137,446 

Coal (29) Sludge/Slurry

c

Land Application 2,323 b

Recycle/Reuse 2,189 b

Underground Injection 1,946 b

Surface Impoundments 1,237 c

Other Processes/Methods 513 b

Container/Tank Storage 107 b

Landfill 64 b

Incineration 6 c

Waste Pile Storage 5 c

Stone, Clay, Glass, and NA

Concrete (32) WWT & Tank Systems 2,210 c

Other Processes/Methods 2,174 c

Surface Impoundments 180 c

Recycle/Reuse 38 c, d

Steel Works, Blasting (331) Aqueous Liquid WWT & Tank Systems 428,486 c

Recycle/Reuse 2,216 b

Surface Impoundments 390 c

Underground Injection 332 b

Other Processes/Methods 258 b

Landfill 47 b

Incineration 19 b

Container/Tank Storage <1 b

Waste Pile Storage <1 c

Iron and Steel Foundries NA Surface Impoundments 1,335 

(332)

c

Waste Pile Storage 39 c

Other Processes/Methods 39 c
Exhibit 8-9 (continued)

Non-Hazardous Industrial Waste Management by Industry

and Waste Type from TSDR and ISDB

Industry Group (SIC) Type(s) Management Type(s) metric tons)

Major Waste (thousand

a,b

Total Amount

Page 8-28

Nonferrous Metals Primary NA WWT & Tank Systems 6,656 

Smelting (333)

c

Landfill 24 c

Recycle/Reuse <1 c

Fabricated Metal Products Aqueous Liquid WWT & Tank Systems 11349 

(34) Sludge/Slurry

c

Surface Impoundments 668 c

Other Processes/Methods 15 c

Incineration 4 c

Landfill 2 b

Recycle/Reuse <1 b

Container/Tank Storage <1 b

Electronics & Other NA WWT & Tank Systems 21,463 

Electronic Equipment (36)

c

Surface Impoundments 1,447 c

Recycle/Reuse 10 c

Incineration 5 c

 NA - No data available

 Includes waste types greater than 1% of total a

 ISDB b

 TSDR; total does not include gases c

 Reuse of fuel only d
Page 8-29

Exhibit 8-10 tabulates by industry the number of waste management units of different types found in the

release descriptions. Of the 120 waste management units identified in the release descriptions, 73 (61 percent)

are landfills, while 28 (23 percent) are surface impoundments. Twelve land application units (10 percent) and 4

waste piles were also identified, along with one trench, 1 evaporation pond, and 1 stormwater retention pond.

These data provide a somewhat different picture than would be expected, merely based on the number of

management units in the various industries and the volumes of wastes managed in different types of units. Despite

the preponderance of landfills in the release descriptions, the vast majority of the non-hazardous industrial

wastes are being managed (or were being managed at the time of the TSS) in surface impoundments. As shown in

Exhibit 8-8, for the industries presented, there are 15,253 surface impoundments versus only 2,757 landfills. 

Several possible explanations for this apparent discrepancy can be advanced. First, better groundwater

monitoring data may be available for landfills than for surface impoundments. Second, management methods may have

changed substantially in the last 11 years. This explanation seems unlikely; surface impoundments or related

treatment systems probably will remain a management method of choice as long as aqueous wastes are the dominant

waste form. Some movement to tanks or other treatment systems may have occurred, and process changes may also have

reduced the volume of liquid wastes, but EPA has no information as to how extensive these changes may have been. In

any event, a large-scale shift away from surface impoundments to landfills seems unlikely, simply based on cost

considerations, even if it was technically feasible for some wastes.

Another possible explanation is that the initial concentrations of potentially toxic constituents may be

lower, on average, for surface impoundments than for landfills, and the highly concentrated solid residues from

the impoundments may themselves end up in landfills, or the surface impoundments may be closed as landfills. 

Finally, design features of non-hazardous industrial waste landfills may make them more prone to releases,

although the other factors just discussed are likely to be more important.

8.3.3 Potential Hazards Associated with Use Constituting Disposal

Few data are available on use that constitutes disposal (UCD) of solid wastes, which is regulated at the

state level. Some data, however, are available for one category of these wastes: certain delisted wastes that are

now being used in a manner constituting disposal. In the first case discussed below, a full risk assessment of UCD

was not done at the time the waste was delisted. In the second case, pending proposals at the federal level would

authorize UCD of delisted wastes; some states, however, may already be permitting some UCD practices for these

wastes under other regulatory provisions.

Delisted K088 (spent potliners from primary aluminum reduction) that has been treated with lime and

heated in a rotary kiln by a specific petitioner and subsequently disposed of primarily in a monofill has caused

high leaching rates of cyanides, fluoride, and arsenic. While the treatment residue passes the TCLP test, the

leachate from the monofill exceeds the TC level for arsenic and the delisting requirements for cyanides and

fluoride. The treatment residual also has a pH of approximately 12.9 and is hazardous and not covered by the

petitioner's exclusion. This K088 treatment residual also has been used for on-site road construction, under a

state RCRA Subtitle D management permit. A recent site inspection found, after rainfall, large puddles of dark

colored water, the same color as the treatment residue used to build the road. Samples of the runoff water are

currently being analyzed.
Page 8-30

Exhibit 8-10

Waste Management Unit Types in the Release Descriptionsa

Industry Group

Evaporation Lagoon/ Surface Land Retention Waste

Pond Impoundment Application Landfill Pond Trench Pile Total

Stormwater

Agricultural Production-Livestock (02) 1 1 2

Apparel and Other Textile Products (23) 1 1

Chemicals and Allied Products (28) 6 5 11

Electric, Gas, Sanitary Services (49) 2 33 35

Electronic and Other Electronic Equipment (36) 1 1 2

Fabricated Metal Products (34) 1 2 1 4

Food and Kindred Products (20) 6 7 13

Industrial Machinery and Equipment (35) 1 1

Instruments and Related Products (38) 1 1

Nonmetallic Minerals, Except Fuels (14) 1 3 4

Paper and Allied Products (26) 5 1 23 29

Petroleum Refining (29) 1 2 1 4

Primary Metal Industries (33) 1 2 1 3 7

Stone, Clay, and Glass Products (32) 1 1 2

Transportation Equipment (37) 1 1 2 4

Total Units 1 28 12 73 1 1 4 120

 A facility may have more than one waste management unit. a
 59 Federal Register 67256, December 29, 1994. 8

Page 8-31

This case raises two issues:

The appropriateness of the TCLP test for evaluating the leaching potential of this waste

treatment residual.

The potential unevaluated risks from runoff from this material when used in a manner

constituting disposal.

The first issue is discussed in Section 3.6. With respect to the second issue, EPA will evaluate the runoff risks

from this site and potentially risks from other instances where states have permitted uses constituting disposal

for non-hazardous industrial waste.

Risks from some UCD practices for some delisted wastes may not be fully understood. Comments on UCD

proposals to allow several uses of high temperature metals recovery (HTMR) slags derived from K061, K062, and F006

listed wastes expressed concern about the completeness of risk evaluation. The proposed rule would allow the de- 8

listed HTMR slags to be used in road building as top grade material, as aggregate in cement, and as anti-skid

material. EPA evaluated the risk from these materials using the TCLP test to estimate potential for leaching to

groundwater. Commentors, however, expressed concerns about risks from surface runoff and wind-blown dust

pathways and risks to workers. At the time of the proposal in December 1994, models to evaluate non-groundwater

pathway risks were not adequately developed. Since then, such models have been developed and were used in a major

rulemaking proposal, the December 1995 HWIR-Waste proposal. These models are undergoing revision in response to

comments by the public and the Science Advisory Board (SAB). The modeling developed to support HWIR-Waste could be

used to evaluate UCD of de-listed HTMR slags or other stabilized waste once the models are refined.

8.3.4 Potential Hazards Associated with Other Management Practices

As noted in Section 8.3.1, it is clear that some non-hazardous industrial wastes are being managed in ways

that do not involve treatment or final disposal in land-based units such as surface impoundments or landfills. 

These other management approaches may also pose potential risks to human health and the environment. In the course

of the Scoping Study, the Agency has found little recent, reliable information as to the types and volumes of nonhazardous industrial wastes being managed using other technologies. A major complication in this regard is that,

unlike the situation for hazardous wastes, generators are not required by federal regulations to identify or

report non-hazardous industrial wastes, process residuals, or byproducts. Thus, any residual or byproduct

material that has potential economic value does not need to be identified as a waste, and instead may simply be used

or sold without restriction. In such cases, the distinction between what constitutes the simple commercial sale

of a material that happens to be a byproduct of an industrial process, recycling, or use constituting disposal of a

non-hazardous industrial waste may not be clear.

Putting this problem aside, it is certain that some non-hazardous wastes are being managed using

techniques other than land storage, treatment, or disposal. Some of these technologies, such as incineration,

unambiguously involve releases to the environment. Others such as recycling and reuse may involve releases,

depending upon the nature of the use of the materials. In EPA’s search for release descriptions, no instances were

found where any of these alternative management methods had resulted in documented environmental releases meeting

the stringent release selection criteria. In addition, as noted previously, the state non-hazardous industrial

waste programs that constitute the major source of the release descriptions may not regulate some of these

alternative waste management technologies. Thus, the available data do not allow a conclusion to be drawn about
Page 8-32

whether and to what extent such management methods may pose significant risks to human health or the environment. 

This data gap is discussed in more detail in Chapter 10.
Page 8-33

CHAPTER 8. POTENTIAL GAPS AS FUNCTION OF INDUSTRY AND WASTE MANAGEMENT METHODS 8-1

8.1 Data Sources and Major Limitations .................................. 8-1

8.2 Potential Gaps as a Function of Industry/Waste Source ................... 8-2

8.2.1 Non-Hazardous Industrial Waste Generation by Industry ........... 8-3

8.2.2 Industries Responsible for Documented Non-Hazardous Industrial Waste

Releases .................................................. 8-5

8.2.3 Occurrence of High-Hazard Industrial Waste Constituents by Industry 8-8

8.2.4 Industries Reporting Releases of TC Analytes or Known or Possible NonHazardous Industrial Waste Constituents ....................... 8-18

8.3 Potential Gaps as a Function of Management Practices .................. 8-21

8.3.1 Waste Management Practices by Waste Type and Industry ......... 8-21

8.3.2 Management Practices Seen in the Release Descriptions ........... 8-28

8.3.3 Potential Hazards Associated with Use Constituting Disposal ...... 8-30

8.3.4 Potential Hazards Associated with Other Management Practices .... 8-31
Page 8-34

Exhibit 8-1 Estimated Generation of Non-Hazardous Industrial Waste by Major Industry Group ... 8-4

Exhibit 8-2 Chemicals Exceeding Health-Based and Non-Health-Based Regulatory Levels in the

Release Descriptions for Non-Hazardous Waste Management ..................... 8-6

Exhibit 8-3 Numbers of Chemical Detections and Frequencies of Regulatory Exceedences in

Release Descriptions ..................................................... 8-7

Exhibit 8-4 Most Frequently Occurring Constituents in the Release Descriptions ............... 8-9

Exhibit 8-5 Occurrence of Waste Constituents by Industry Group .......................... 8-11

Exhibit 8-6 Non-Hazardous Industrial Waste Constituents Reported Released by Industry ....... 8-19

Exhibit 8-7 Volume of Non-Hazardous Industrial Waste Managed in Land-Based Facilities in

1985 ................................................................. 8-22

Exhibit 8-8 Active Non-Hazardous Industrial Waste Management Units in 1985 by Major

Industry Group ......................................................... 8-23

Exhibit 8-9 Non-Hazardous Industrial Waste Management by Industry and Waste Type from TSDR

and ISDB ............................................................. 8-24

Exhibit 8-10 Waste Management Unit Types in the Release Descriptions ..................... 8-29
EXHIBIT 8-6 TRI REPORTED RELEASES TO LAND OR UNDERGROUND INJECTION BY CONSTITUENT AND INDUSTRY

Type of SIC 20 SIC 21 SIC 22 SIC 24 SIC 25 SIC 26 SIC 27 SIC 28 SIC 29 SIC 30 SIC 31

Chemical Namea Chemical UI L UI L UI L UI L UI L UI L UI L UI L UI L UI L UI L

1,1,1-TRICHLOROETHANE VCO 5 25 0 0 0 0 0 0 0 5,800 0 0 0 975 553 1,826 0 288 0 17,403 0 0

1,2-DICHLOROETHANE VCO 0 1,000 0 0 0 0 0 0 0 0 0 0 0 0 6,927 858 0 0 0 0 0 0

1,3-BUTADIENE VO 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1,000 372 0 0 0 0 0 0

ACETALDEHYDE OVO 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1,905,859 289 0 0 0 0 0 0

ACETONITRILE OVO 0 0 0 0 0 0 0 0 0 0 0 0 0 0 20,111,640 29 0 0 0 0 0 0

ACRYLAMIDE OSO 0 0 0 0 0 0 0 0 0 0 0 0 0 0 4,188,680 963 0 0 0 0 0 0

ACRYLONITRILE OVO 0 0 0 0 0 0 0 0 0 0 0 30 0 0 3,795,670 387 0 0 0 7,654 0 0

ANILINE OSO 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1,195,676 1,173 0 0 0 0 0 0

BENZENE VO 0 0 0 0 0 0 0 0 0 0 0 0 0 0 268,921 225,952 78,162 114,164 0 0 0 0

BROMOMETHANE OVO 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1,000 0 0 0 0 0 0 0

CARBON DISULFIDE OVO 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2,704 5 0 16 0 0 0 0

CHLOROBENZENE VCO 0 0 0 0 0 0 0 0 0 0 0 0 0 0 72,000 817 0 0 0 0 0 0

CHLOROFORM VCO 0 0 0 0 0 0 0 0 0 0 0 11,582 0 0 50,240 17,000 0 0 0 0 0 0

CHLOROMETHANE VCO 0 0 0 0 0 0 0 0 0 0 0 0 0 0 86,709 0 0 0 0 0 0 0

CHLOROPRENE VCO 0 0 0 0 0 0 0 0 0 0 0 0 0 0 54,000 0 0 0 0 1,811 0 0

CHROMIUM IO 0 0 0 0 0 0 5 0 0 0 0 0 0 0 0 4,550 0 2,226 0 2 0 7,707

COPPER M/I 0 0 0 0 0 0 5 250 0 0 0 0 0 0 16,460 14,810 0 0 0 0 0 0

CUMENE VH 0 0 0 0 0 0 0 0 0 0 0 0 0 0 11,000 315 4,100 468 0 0 0 0

DICHLORODIFLUOROMETHANE VCO 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1,722 23 0 0 0 0 0 0

DICHLOROMETHANE VCO 0 2,100 0 0 0 0 0 0 0 0 0 251 0 0 1,183,867 377 0 10 0 46,620 0 0

ETHYLBENZENE VH 0 0 0 0 0 0 0 0 0 250 0 0 0 0 190,648 5,735 3,234 271,175 0 0 0 0

FORMALDEHYDE OVO 0 200 0 0 0 0 0 10,139 0 0 0 4,336 0 0 4,916,248 16,314 0 0 0 0 0 0

FREON 113 CFC 0 0 0 0 0 0 0 0 0 0 0 0 0 0 17 6 0 0 0 0 0 0

METHANOL OVO 0 20,250 0 0 0 12,482 0 17,495 0 80,327 0 2,957,167 0 3,000 26,852,673 220,185 230,590 1,582 0 0 0 0

METHYL ETHYL KETONE OVO 0 0 0 0 0 0 0 250 0 27,931 0 6,873 0 0 325,390 26,226 40,000 748 0 10,770 0 0

METHYL ISOBUTYL KETONE OVO 0 0 0 0 0 0 0 0 0 139,400 0 0 0 0 129,100 1,823 0 35 0 0 0 0

METHYL METHACRYLATE OVO 0 0 0 0 0 0 0 0 0 0 0 11 0 0 220,000 1,742 0 0 0 2,250 0 0

N-BUTYL ALCOHOL OVO 0 0 0 0 0 0 0 0 0 8,856 0 0 0 0 2,324,731 519 0 0 0 0 0 0

NAPHTHALENE OSO 0 0 0 5 0 0 0 1 0 0 0 8,445 0 0 60,654 23,191 573 1,539,299 0 0 0 0

PROPYLENE OXIDE OVO 0 0 0 0 0 0 0 0 0 0 0 0 0 0 200 2,251 0 0 0 0 0 0

STYRENE VH 0 0 0 0 0 0 0 0 0 0 0 5 0 0 83,170 60,330 0 0 0 141,153 0 0

TETRACHLOROETHYLENE VCO 0 0 0 0 0 0 0 0 0 0 0 0 0 0 12,780 4,264 0 0 0 1,495 0 0

TOLUENE VH 0 0 0 0 0 0 0 434 0 65,114 0 798 0 4,300 1,547,118 26,211 26,778 546,483 0 5 0 0

TRICHLOROETHYLENE VCO 0 0 0 0 0 0 0 0 0 0 0 0 0 0 466 1 0 0 0 0 0 0

TRICHLOROFLUOROMETHANE VCO 0 0 0 0 0 0 0 0 0 0 0 0 0 0 8 18,912 0 0 0 0 0 0

VINYL CHLORIDE VCO 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 6 0 0 0 0 0 3,100

XYLENE (MIXED ISOMERS) VH 0 0 0 0 0 0 1 0 0 44,914 0 250 0 40 200,309 3,129 18,835 1,142,430 5 0 0 0

ZINC (FUME OR DUST) M/I 0 250 0 0 0 5 0 5 0 0 0 1,100 0 0 120,000 28,710 0 0 0 250 0 0

Total 5 23,825 0 5 0 12,487 11 28,574 0 372,592 0 2,990,848 0 8,315 69,938,141 709,301 402,272 3,618,924 5 229,413 0 10,807

Source: 1992 TRI data.

UI = Underground Injection Industry Groups (SIC) 30 = Rubber and Miscellaneous Plastics Products

L = Land 20 = Food and Kindred Products 31 = Leather and Leather Products

VCO = Volatile Chlorinated Organics 21 = Tobacco Products 32 = Stone, Clay and Glass Products

OVO = Other Volatile Organics 22 = Textile Mill Products 33 = Primary Metal Industries

OSO = Other Semivolatile Organics 24 = Lumber and Wood Products 34 = Fabricated Metal Products

M/I = Metals/Inorganics 25 = Furniture and Fixtures 35 = Industrial Machinery and Equipment

VH = Volatile Hydrocarbons 26 = Paper and Allied Products 36 = Electronic and Other Electronic Equipment

IO = Inorganics 27 = Printing and Publishing 37 = Transportation Equipment

VO = Volatile Organics 28 = Chemicals and Allied Products 38 = Instruments and Related Products

CFC = Chlorofluorocarbons 29 = Petroleum Refining 39 = Miscellaneous Manufacturing Products

8-6a.txt
EXHIBIT 8-6 TRI REPORTED RELEASES TO LAND OR UNDERGROUND INJECTION BY CONSTITUENT AND INDUSTRY (continued)

Type of SIC 20 SIC 21 SIC 22 SIC 24 SIC 25 SIC 26 SIC 27 SIC 28 SIC 29 SIC 30 SIC 31

Chemical Namea Chemical UI L UI L UI L UI L UI L UI L UI L UI L UI L UI L UI L

1,1,1-TRICHLOROETHANE VCO 5 25 0 0 0 0 0 0 0 5,800 0 0 0 975 553 1,826 0 288 0 17,403 0 0

1,2-DICHLOROETHANE VCO 0 1,000 0 0 0 0 0 0 0 0 0 0 0 0 6,927 858 0 0 0 0 0 0

1,3-BUTADIENE VO 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1,000 372 0 0 0 0 0 0

ACETALDEHYDE OVO 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1,905,859 289 0 0 0 0 0 0

ACETONITRILE OVO 0 0 0 0 0 0 0 0 0 0 0 0 0 0 20,111,640 29 0 0 0 0 0 0

ACRYLAMIDE OSO 0 0 0 0 0 0 0 0 0 0 0 0 0 0 4,188,680 963 0 0 0 0 0 0

ACRYLONITRILE OVO 0 0 0 0 0 0 0 0 0 0 0 30 0 0 3,795,670 387 0 0 0 7,654 0 0

ANILINE OSO 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1,195,676 1,173 0 0 0 0 0 0

BENZENE VO 0 0 0 0 0 0 0 0 0 0 0 0 0 0 268,921 225,952 78,162 114,164 0 0 0 0

BROMOMETHANE OVO 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1,000 0 0 0 0 0 0 0

CARBON DISULFIDE OVO 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2,704 5 0 16 0 0 0 0

CHLOROBENZENE VCO 0 0 0 0 0 0 0 0 0 0 0 0 0 0 72,000 817 0 0 0 0 0 0

CHLOROFORM VCO 0 0 0 0 0 0 0 0 0 0 0 11,582 0 0 50,240 17,000 0 0 0 0 0 0

CHLOROMETHANE VCO 0 0 0 0 0 0 0 0 0 0 0 0 0 0 86,709 0 0 0 0 0 0 0

CHLOROPRENE VCO 0 0 0 0 0 0 0 0 0 0 0 0 0 0 54,000 0 0 0 0 1,811 0 0

CHROMIUM IO 0 0 0 0 0 0 5 0 0 0 0 0 0 0 0 4,550 0 2,226 0 2 0 7,707

COPPER M/I 0 0 0 0 0 0 5 250 0 0 0 0 0 0 16,460 14,810 0 0 0 0 0 0

CUMENE VH 0 0 0 0 0 0 0 0 0 0 0 0 0 0 11,000 315 4,100 468 0 0 0 0

DICHLORODIFLUOROMETHANE VCO 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1,722 23 0 0 0 0 0 0

DICHLOROMETHANE VCO 0 2,100 0 0 0 0 0 0 0 0 0 251 0 0 1,183,867 377 0 10 0 46,620 0 0

ETHYLBENZENE VH 0 0 0 0 0 0 0 0 0 250 0 0 0 0 190,648 5,735 3,234 271,175 0 0 0 0

FORMALDEHYDE OVO 0 200 0 0 0 0 0 10,139 0 0 0 4,336 0 0 4,916,248 16,314 0 0 0 0 0 0

FREON 113 CFC 0 0 0 0 0 0 0 0 0 0 0 0 0 0 17 6 0 0 0 0 0 0

METHANOL OVO 0 20,250 0 0 0 12,482 0 17,495 0 80,327 0 2,957,167 0 3,000 26,852,673 220,185 230,590 1,582 0 0 0 0

METHYL ETHYL KETONE OVO 0 0 0 0 0 0 0 250 0 27,931 0 6,873 0 0 325,390 26,226 40,000 748 0 10,770 0 0

METHYL ISOBUTYL KETONE OVO 0 0 0 0 0 0 0 0 0 139,400 0 0 0 0 129,100 1,823 0 35 0 0 0 0

METHYL METHACRYLATE OVO 0 0 0 0 0 0 0 0 0 0 0 11 0 0 220,000 1,742 0 0 0 2,250 0 0

N-BUTYL ALCOHOL OVO 0 0 0 0 0 0 0 0 0 8,856 0 0 0 0 2,324,731 519 0 0 0 0 0 0

NAPHTHALENE OSO 0 0 0 5 0 0 0 1 0 0 0 8,445 0 0 60,654 23,191 573 1,539,299 0 0 0 0

PROPYLENE OXIDE OVO 0 0 0 0 0 0 0 0 0 0 0 0 0 0 200 2,251 0 0 0 0 0 0

STYRENE VH 0 0 0 0 0 0 0 0 0 0 0 5 0 0 83,170 60,330 0 0 0 141,153 0 0

TETRACHLOROETHYLENE VCO 0 0 0 0 0 0 0 0 0 0 0 0 0 0 12,780 4,264 0 0 0 1,495 0 0

TOLUENE VH 0 0 0 0 0 0 0 434 0 65,114 0 798 0 4,300 1,547,118 26,211 26,778 546,483 0 5 0 0

TRICHLOROETHYLENE VCO 0 0 0 0 0 0 0 0 0 0 0 0 0 0 466 1 0 0 0 0 0 0

TRICHLOROFLUOROMETHANE VCO 0 0 0 0 0 0 0 0 0 0 0 0 0 0 8 18,912 0 0 0 0 0 0

VINYL CHLORIDE VCO 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 6 0 0 0 0 0 3,100

XYLENE (MIXED ISOMERS) VH 0 0 0 0 0 0 1 0 0 44,914 0 250 0 40 200,309 3,129 18,835 1,142,430 5 0 0 0

ZINC (FUME OR DUST) M/I 0 250 0 0 0 5 0 5 0 0 0 1,100 0 0 120,000 28,710 0 0 0 250 0 0

Total 5 23,825 0 5 0 12,487 11 28,574 0 372,592 0 2,990,848 0 8,315 69,938,141 709,301 402,272 3,618,924 5 229,413 0 10,807

Source: 1992 TRI data.

UI = Underground Injection Industry Groups (SIC) 30 = Rubber and Miscellaneous Plastics Products

L = Land 20 = Food and Kindred Products 31 = Leather and Leather Products

VCO = Volatile Chlorinated Organics 21 = Tobacco Products 32 = Stone, Clay and Glass Products

OVO = Other Volatile Organics 22 = Textile Mill Products 33 = Primary Metal Industries

OSO = Other Semivolatile Organics 24 = Lumber and Wood Products 34 = Fabricated Metal Products

M/I = Metals/Inorganics 25 = Furniture and Fixtures 35 = Industrial Machinery and Equipment

VH = Volatile Hydrocarbons 26 = Paper and Allied Products 36 = Electronic and Other Electronic Equipment

IO = Inorganics 27 = Printing and Publishing 37 = Transportation Equipment

VO = Volatile Organics 28 = Chemicals and Allied Products 38 = Instruments and Related Products

CFC = Chlorofluorocarbons 29 = Petroleum Refining 39 = Miscellaneous Manufacturing Products

8-6b.txt
EXHIBIT 8-6 TRI REPORTED RELEASES TO LAND OR UNDERGROUND INJECTION BY CONSTITUENT AND INDUSTRY (continued)

Type of

Chemical Namea Chemical

1,1,1-TRICHLOROETHANE VCO

1,2-DICHLOROETHANE VCO

1,3-BUTADIENE VO

ACETALDEHYDE OVO

ACETONITRILE OVO

ACRYLAMIDE OSO

ACRYLONITRILE OVO

ANILINE OSO

BENZENE VO

BROMOMETHANE OVO

CARBON DISULFIDE OVO

CHLOROBENZENE VCO

CHLOROFORM VCO

CHLOROMETHANE VCO

CHLOROPRENE VCO

CHROMIUM IO

COPPER M/I

CUMENE VH

DICHLORODIFLUOROMETHANE VCO

DICHLOROMETHANE VCO

ETHYLBENZENE VH

FORMALDEHYDE OVO

FREON 113 CFC

METHANOL OVO

METHYL ETHYL KETONE OVO

METHYL ISOBUTYL KETONE OVO

METHYL METHACRYLATE OVO

N-BUTYL ALCOHOL OVO

NAPHTHALENE OSO

PROPYLENE OXIDE OVO

STYRENE VH

TETRACHLOROETHYLENE VCO

TOLUENE VH

TRICHLOROETHYLENE VCO

TRICHLOROFLUOROMETHANE VCO

VINYL CHLORIDE VCO

XYLENE (MIXED ISOMERS) VH

ZINC (FUME OR DUST) M/I

Total

SIC 32 SIC 33 SIC 34 SIC 35 SIC 36 SIC 37 SIC 38 SIC 39 Invalid Total

UI L UI L UI L UI L UI L UI L UI L UI L UI L Total UI Total Land Combined

0 0 0 2,916 0 39,778 0 6,805 3 10 0 200 0 350 0 0 0 0 561 76,381 76,942

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 6,927 1,858 8,785

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1,000 372 1,372

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1,905,859 289 1,906,148

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 20,111,640 29 20,111,669

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 4,188,680 963 4,189,643

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 65,880 0 3,861,550 8,071 3,869,621

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1,195,676 1,173 1,196,849

0 0 8,600 500 0 0 0 0 0 0 0 20 0 0 0 0 0 0 355,683 340,636 696,319

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1,000 0 1,000

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2,704 21 2,725

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 72,000 817 72,817

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 50,240 28,582 78,822

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 86,709 0 86,709

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 54,000 1,811 55,811

0 10,526 8 842,104 70 75,306 0 13,226 0 500 250 455 0 510 0 0 0 0 333 957,112 957,445

0 767 271 12,579,039 0 18,368 0 2,620 0 25,709 0 5,130 0 0 0 645 0 0 16,736 12,647,338 12,664,074

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 15,100 783 15,883

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1,722 23 1,745

0 77 0 12,705 0 0 0 17,101 0 12 0 0 0 60 0 0 0 0 1,183,867 79,313 1,263,180

0 0 0 0 0 11,510 0 48 0 0 0 0 0 0 0 0 0 390 193,882 289,108 482,990

0 105,331 0 38,109 0 0 0 0 0 0 0 0 0 0 0 0 0 0 4,916,248 174,429 5,090,677

0 0 0 0 0 0 0 0 197 850 0 250 0 7,922 0 0 0 0 214 9,028 9,242

0 0 0 411 0 4,296 0 2,305 169 0 0 9,041 0 0 0 0 750 0 27,084,182 3,328,541 30,412,723

0 0 0 0 0 95,930 0 62,575 5 0 0 8,291 0 1,500 0 0 0 700 365,395 241,794 607,189

0 0 0 750 0 23,381 0 21,235 0 0 0 8,291 0 0 0 0 0 71 129,100 194,986 324,086

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 220,000 4,003 224,003

0 0 0 0 0 46,865 0 190 0 0 0 0 0 0 0 0 0 790 2,324,731 57,220 2,381,951

0 0 17,000 96,200 0 0 0 0 0 0 0 0 0 0 0 0 0 0 78,227 1,667,141 1,745,368

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 200 2,251 2,451

0 97,000 0 5 0 0 0 0 0 0 0 5,686 0 0 0 0 0 0 83,170 304,179 387,349

0 5 0 0 0 3,585 0 5 0 0 0 0 0 0 0 0 0 0 12,780 9,354 22,134

0 4,926 0 750 0 41,652 0 4,196 5 5 0 8,944 0 0 0 250 0 4,210 1,573,901 708,278 2,282,179

0 0 0 10,050 0 2,250 0 0 0 0 0 8,420 0 5 0 0 0 0 466 20,726 21,192

0 0 0 0 0 250 0 599 0 0 0 0 0 0 0 0 0 0 8 19,761 19,769

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 3,106 3,107

0 5 0 102,068 0 104,695 0 1,337 120 4,350 0 10,961 0 0 0 250 0 10,600 219,270 1,434,429 1,653,699

0 0 0 12,785,679 0 122,303 0 0 0 0 0 102,816 0 0 0 0 0 5 120,000 13,041,123 13,161,123

0 218,637 25,879 26,471,286 70 590,169 0 132,242 499 31,436 250 168,505 0 10,347 0 1,145 66,630 16,766 70,433,762 35,655,029 106,088,791

Source: 1992 TRI data.

UI = Underground Injection Industry Groups (SIC) 30 = Rubber and Miscellaneous Plastics Products

L = Land 20 = Food and Kindred Products 31 = Leather and Leather Products

VCO = Volatile Chlorinated Organics 21 = Tobacco Products 32 = Stone, Clay and Glass Products

OVO = Other Volatile Organics 22 = Textile Mill Products 33 = Primary Metal Industries

OSO = Other Semivolatile Organics 24 = Lumber and Wood Products 34 = Fabricated Metal Products

M/I = Metals/Inorganics 25 = Furniture and Fixtures 35 = Industrial Machinery and Equipment

VH = Volatile Hydrocarbons 26 = Paper and Allied Products 36 = Electronic and Other Electronic Equipment

IO = Inorganics 27 = Printing and Publishing 37 = Transportation Equipment

VO = Volatile Organics 28 = Chemicals and Allied Products 38 = Instruments and Related Products

CFC = Chlorofluorocarbons 29 = Petroleum Refining 39 = Miscellaneous Manufacturing Products

8-6b.txt
 Constituents are included in Appendix VIII if a reputable scientific study has found that the constituent has toxic,

1

carcinogenic, mutagenic, or teratogenic effects on humans or other forms of life.

Page 9-1

CHAPTER 9. POTENTIAL FOR GAPS TO BE ADDRESSED

BY EXISTING REGULATIONS

The potential gaps described in Chapters 3 and 4 of this Scoping Study were identified solely in terms of

their relationship to non-hazardous industrial waste management, and not with regard to whether they might be

controlled under RCRA or other regulatory programs. This chapter examines the extent to which existing regulatory

programs may already address these potential gaps and thereby helps to evaluate the extent of the potential gaps. 

The programs reviewed are as follows:

RCRA,

Clean Water Act (CWA),

Safe Drinking Water Act (SDWA),

Clean Air Act (CAA),

Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA),

Toxic Substances Control Act (TSCA),

Pollution prevention initiatives,

Occupational Safety and Health Act (OSHA), and

Hazardous Materials Transportation Act (HMTA).

The regulatory control provided by these programs is reviewed in general terms, rather than in detail. Further

analysis would be necessary to determine the precise degree of protection that these programs provide against

particular risks.

9.1 RCRA Programs

Where there are gaps in the hazardous waste characteristics, the RCRA hazardous waste listings and

Subtitle D program may reduce any resulting human health and environmental risks. These two programs are

discussed below, including both the direct federal regulatory authorities and state-delegated authorities.

9.1.1 Hazardous Waste Programs

As described in RCRA Section 3001(a)-(b), EPA is required to develop regulations that both specify

criteria for listing hazardous waste and to list particular hazardous wastes. In 40 CFR 261.11, EPA has specified

three criteria for listing solid wastes as hazardous:

The waste exhibits a hazardous characteristic;

The waste is acutely hazardous because is has been found to be fatal to humans in low

doses, or is otherwise capable of causing or significantly contributing to an increase

in serious irreversible, or incapacitating reversible, illness; or

The waste contains a toxic constituent listed in 40 CFR Part 261, Appendix VIII and, 1

after considering several risk-based and non risk-based factors, is capable of posing a
Page 9-2

substantial present or potential hazard to human health or the environment when

improperly treated, stored, transported, or disposed of, or otherwise managed.

EPA has established four hazardous waste lists: 

Hazardous waste from non-specific sources, or F wastes;

Hazardous wastes from specific sources, or K wastes;

Discarded commercial chemicals that are toxic, or P wastes; and

Discarded commercial chemicals that are acutely hazardous, or U wastes.

Because the F and K listings focus on waste streams, rather than on particular constituents, identification of a

chemical as a constituent in a listed F or K waste does not automatically imply that all or most industrial wastes

containing that constituent are regulated by the hazardous waste listings. For example, the F003 listing

regulates benzene when it is a spent solvent, but does not regulate other benzene-containing wastes such as

petroleum refining wastes. Similarly, for a chemical to be controlled by a P or U listing, it must be a discarded

commercial product. If the source of the chemical is different (e.g., from a waste mixture that is not covered by

an F or K listing), it is not regulated as a listed waste. For example, 2,4-dimethylphenol, which is a listed U

waste (U101) when it is a discarded commercial chemical, was found among the environmental releases from nonhazardous industrial waste management documented in Chapter 2. This chemical also was found in the other two

sources of data on non-hazardous industrial waste constituents, the Industrial Studies Database (ISDB) and the

Effluent Guidelines Development Documents.

40 CFR Part 261, Appendix VII contains the majority of the "known" non-hazardous industrial waste

constituents, including:

40 of the 41 known non-hazardous industrial waste constituents found in all three major

data sources: the release descriptions, ISDB, and the effluent guideline development

documents data; and

134 of all 248 known constituents.

Although Appendix VII constituents are the basis for individual hazardous waste listings, they also appear in nonhazardous industrial wastes. The listings, therefore, do not regulate all wastes containing these constituents.

Most states have developed their own hazardous waste programs and have received EPA approval to implement

their regulations in lieu of the federal program. These state hazardous waste regulations may be broader or more

stringent than federal RCRA Subtitle C regulations. A number of states have done so by regulating additional

wastes as hazardous. For example, states have:

Expanded the ignitability, corrosivity, or reactivity (ICR) characteristics;

Expanded the toxicity characteristic (TC);

Listed wastes as hazardous that are not hazardous under the federal rules; and

Restricted exemptions from the federal program.

These expansions beyond the federal hazardous waste identification rules, which are discussed in Chapter 6,

reflect state judgments about gaps in the federal program and thereby fill these potential gaps in particular

states. Conversely, these expansions constitute potential gaps in other states.

9.1.2 Subtitle D
Page 9-3

States have primary responsibility for managing non-hazardous industrial wastes. Under RCRA Subtitle D,

the Federal Government only establishes minimum criteria that prescribe the best practicable controls and

monitoring requirements for non-hazardous waste disposal facilities. EPA has developed separate criteria for

municipal solid waste landfills (MSWLFs), which must comply with the requirements of 40 CFR Part 258, and for nonhazardous industrial (Industrial D) land application units, which must comply with the requirements of 40 CFR Part

257.

40 CFR Part 258 specifies six categories of MSWLF criteria: location, operation, design, ground-water

monitoring and corrective action, closure and post-closure care, and financial assurance. Most relevant to

addressing potential gaps in the characteristics, any leachate from new MSWLFs (which began accepting waste after

October 9, 1993) must not cause contaminant levels in the uppermost aquifer to exceed maximum contaminant levels

(MCLs) specified under the Safe Drinking Water Act. In addition, all MSWLFs must be operated in a way that ensures

that they do not release pollutants that violate the Clean Water Act. Beyond meeting the minimum federal criteria,

approved States are permitted to develop their own standards for MSWLFs.

The operating and design requirements for MSWLFs under Part 258 are designed to allow protective disposal

of conditionally exempt small quantity generator hazardous waste (CESQG). As a result, MSWLFs can accept nonhazardous and CESQG waste from both municipal and industrial sources. Industrial D landfills can accept

conditionally exempt small quantity generator (CESQG) waste (e.g., construction and demolition waste) only if

they meet the location, groundwater monitoring and corrective action requirements specified in 40 CFR Part 257. 

Industrial D landfills that do not meet these requirements are not permitted to accept CESQG waste.

To a limited extent, state non-hazardous industrial waste management programs address potential gaps in

the hazardous waste characteristics. These state programs, however, vary considerably in the types of

requirements imposed, the stringency of such requirements, and even the types of waste management units regulated. 

They do not provide uniform national coverage of non-hazardous industrial waste management. For example, despite

the state requirements placed on these landfills, about 50 chemicals were found in the release descriptions at

concentrations above MCLs, including a number of metals (e.g., zinc, nickel, mercury, and lead) and volatile

chlorinated organics (e.g., vinyl chloride, carbon tetrachloride, chlorobenzene, and chloroform). Similarly,

about 90 percent of all releases were found to be associated with unlined management units; not all states

currently require Industrial D units to be lined.

9.2 Medium-Specific Regulations

Medium-specific regulations such as the Clean Water Act, the Safe Drinking Water Act, and the Clean Air

Act can both directly and indirectly address potential gaps in the hazardous waste characteristics. These

programs regulate exposure via specific pathways of potential concern for non-hazardous industrial wastes, as

discussed in Chapters 3 and 4. Medium-specific regulations also could indirectly address potential gaps by

discouraging or preventing the occurrence of the specific constituents in non-hazardous industrial waste. For

example, CWA regulations may cause a manufacturer to alter a production process so that a particular chemical that

requires control is not used in the production process, thereby eliminating that constituent from its solid waste

stream. Where substitutions or alterations in the production process are not feasible, however, the mediumspecific regulations could result in cross medium transfers, increasing the use of solid waste disposal as the

preferred management method of the regulated constituents. The net effect of these two incentives on solid waste

disposal practices is uncertain.

9.2.1 Clean Water Act

The CWA is designed to restore and protect the physical, chemical, and biological quality of the nation's

surface waters. To achieve this goal, all discharges to navigable waters must be permitted. To help permit
Page 9-4

writers, EPA has established effluent limitations for 127 toxic pollutants on direct discharges to waters by 34

industrial source categories and publicly-owned treatment works (POTWs). Permit writers use these guidelines to

establish discharge limits and other permit conditions. Where effluent guidelines do not exist for an industry,

permit writers use best engineering judgment to determine appropriate permit conditions.

CWA regulations and permits directly limit exposures through surface water pathways. The CWA also

indirectly addresses exposures to CWA regulated chemicals though other pathways by providing incentives for

reducing or eliminating the use of such chemicals or for cross-media transfer of such chemicals. 

Chapter 3 identified three potential gaps in the current toxicity characteristic that may be addressed to

some extent by the Clean Water Act:

Potential risks from direct surface water exposures;

Potential indirect pathway risks involving surface waters; and

Potential risks to ecological receptors involving surface waters.

As discussed in Chapter 3, surface water exposure pathways may be significant for some TC analytes

disposed as non-hazardous industrial waste. Because run-off waters from landfills must be managed according to

the requirements of the CWA, risks to human health from surface water exposures are addressed if these TC analytes

have effluent limits established under the CWA. These effluent limits may also address risks to ecological

receptors from exposure surface water, principally at water bodies near waste management units contaminated from

surface water run-off. In addition, persistent and bioaccumulative chemicals discharged to surface waters may

contaminate fish and shellfish that, when consumed, cause indirect exposure risk to human health. CWA effluent

limits can address indirect exposure risks from those TC analytes for which effluent limits are established.

As Exhibit 9-1 demonstrates, CWA effluent limits are established for 28 of the TC constituents, including

all of the TC metals except barium. Many of these TC constituents are commonly found in the release descriptions. 

For example, 7 of the top 20 frequently occurring constituents in the release descriptions are TC metals. Other TC

constituents occurring five or more times in the release descriptions that have CWA effluent limits include

benzene, vinyl chloride, chloroform, chlorobenzene, and tetrachloroethylene. Among these constituents,

chlorobenzene, mercury, and lead can pose risks to ecological receptors.
Page 9-5

Exhibit 9-1

TC Constituents with Effluent Limits Established under CWA

TC Analyte Limit TC Analyte Limit TC Analyte Limit

CWA CWA CWA

Effluent Effluent Effluent

1,1-Dichloroethylene -- Chloroform Methyl ethyl ketone --

1,2-Dichloroethane Chromium Nitrobenzene

1,4-Dichlorobenzene Cresol (mixed isomers) -- o-Cresol --

2,4,5-Trichlorophenol -- Endrin p-Cresol --

2,4,6-Trichlorophenol Heptachlor Pentachlorophenol

2,4-D, salts and esters -- Heptachlor epoxide Pyridine --

2,4-Dinitrotoluene Hexachlorobenzene Selenium

Arsenic Hexachloro-1,3-butadiene -- Silver

Barium -- Hexachloroethane Silvex (2,4,5-TP) --

Benzene Lead Tetrachloroethylene

Cadmium Lindane Toxaphene

Carbon tetrachloride m-Cresol -- Trichloroethylene

Chlordane Mercury Vinyl chloride

Chlorobenzene Methoxychlor --

The CWA effluent limitations may also address some of the potential gaps identified in Chapter 4 that are

associated with non-TC constituents, including indirect pathway exposures to phenolic compounds, DNAPL formation

by chlorinated organics, indirect pathway exposure to PAHs, and indirect pathway exposure to phthalate esters. 

For the CWA to address indirect pathway exposures to these chemicals, releases to surface water from regulated

facilities must be involved. Exhibit 9-2 lists chemicals representative of these potential gaps and indicates

which chemicals are subject to CWA effluent limitations. Effluent limitations are specified for 7 of the 8 and for

15 of the 18 phenols and PAHs, respectively, on the list of known non-hazardous industrial waste constituents. CWA

effluent limitations also control surface water releases of the chemicals that are likely to form DNAPLs,

including halogenated chemicals. Exhibit 9-2 lists 35 known non-hazardous volatile chlorinated organics. Of

these chemicals, 18 are subject to effluent guideline limits. CWA effluent limitations are specified for all six

of the phthalate esters on the list of known non-hazardous industrial waste constituents. Phthalate esters are

one class of chemical that bioaccumulate in the environment and may be endocrine disruptors.
Page 9-6

Exhibit 9-2

CWA Effluent Limitations Relevant to Certain Known Non-Hazardous Industrial Waste Constituents

Phenols Limit DNAPL formers) Limit PAHs Limit

CWA CWA CWA

Effluent Volatile Chlorinated Organics (Potential Effluent Effluent

2,4-Dimethylphenol 1,1,1,2-Tetrachloroethane -- 2-Methylnaphthalene --

2,4-Dinitrophenol 1,1,1-Trichloroethane 7,12-Dimethylbenz[a]anthracene --

2-Nitrophenol 1,1,2,2-Tetrachloroethane Acenaphthene

4,6-Dinitro-o-cresol 1,1,2-Trichloroethane Acenaphthylene

4-Nitrophenol 1,2,3-Trichloropropane -- Anthracene

p-Chloro-m-cresol 1,2,4,5-Tetrachlorobenzene -- Benz[a]anthracene

Phenol 1,2,4-Trichlorobenzene Benzo(a)phenanthrene

Phenolics -- 1,2-Dibromo-3-chloropropane -- Benzo(k)fluoranthene

1,2-Dichlorobenzene Benzo[a]pyrene

1,2-Dichloroethylene -- Benzo[b]fluoranthene

1,2-Dichloroethylene, trans Benzo[ghi]perylene

1,2-Dichloropropane Dibenz[a,h]anthracene

1,3-Dichlorobenzene Fluoranthene

1,3-Dichloropropylene Fluorene

Allyl chloride -- Indeno(1,2,3-cd)pyrene

Benzoic trichloride -- Isophorone

Bis(2-chloroethyl) ether Methapyrilene --

Chlorobromomethane -- Pyrene

Chlorodibromomethane

Chloroethane

Chloromethane

cis-1,2-Dichloroethylene --

Dichloro-2-propanol, 1,3- --

Dichlorobromomethane

Dichlorodifluoromethane --

Dichloromethane

Dichloropropane --

Epichlorohydrin --

Ethylidene Dichloride

Hexachlorocyclopentadiene

Pentachloroethane --

Tetrachloroethane, N.O.S. --

trans-1,3-Dichloropropene

Trichlorofluoromethane --

Trichloromethanethiol --

As shown in Exhibit 9-3, considerable overlap exists between the industries with established effluent

limits under the CWA and those industries responsible for the releases described in Chapter 2 (see Exhibit 2-3). 

For example, EPA has established CWA effluent limitations for the paper, chemical manufacturing, and primary

metals industries, but not for electric, gas, and sanitary services; the food industry; and the non-metallic

minerals industry. Further analysis is necessary to determine whether the chemicals covered by the effluent

guidelines for these industries appear in their documented releases.
Page 9-7

Exhibit 9-3

CWA Coverage of Industries Represented in Release Descriptions

Industry Group SIC Code Releases CWA Effluent Limitations

Total Number of

Electric, Gas, and Sanitary 49 35 no

Services (refuse only)

Paper and Allied Products 26 27 yes

Chemicals and Allied Products 28 11 yes; separates organic and inorganic

manufacturing

Food and Kindred Products 20 10 no

Primary Metals 33 6 yes; separates nonferrous and iron/steel

manufacturing

Non-Metallic Minerals 14 4 no

9.2.2 Safe Drinking Water Act

Under the Safe Drinking Water Act, EPA has identified contaminants in drinking water that may adversely

affect human health. For each contaminant, EPA has established a maximum contaminant level (MCL) that must not be

exceeded in drinking water. MCLs are based on maximum contaminant level goals (MCLGs), which are the nonenforceable health-based levels at which no known or anticipated adverse effects on the health of people occur and

which allow an adequate margin of safety. MCLGs are adjusted to MCLs based on considerations of feasibility,

including technical implementation and economic considerations. As discussed in Section 5.1, EPA also has

established non-health based or non-ecological based drinking water standards, based principally on aesthetic or

usability criteria, which are called Secondary MCLs (SMCLs). 

The MCL standards apply to public water systems that regularly supply water to 15 or more connections or to

25 or more individuals at least 60 days per year in the case of residential populations or at least 6 months per

year in the case of non-residential populations. The SDWA also regulates, through EPA or approved state programs,

the underground injection of wastes to protect aquifers that are or may reasonably be expected to be sources of

drinking water. These aquifers must be protected from contamination that violates an MCL or otherwise adversely

affect human health. 

The SDWA has become important beyond the regulation of public water systems and underground injection of

waste because the MCLs have been used in other regulatory contexts. For example, RCRA Subtitle D regulations for

municipal solid waste landfills specify that MCLs must not be exceeded in the uppermost aquifer underlying a

landfill.

Because the regulatory levels established under the SDWA apply only to public water systems, its ability

to address potential gaps resulting from non-hazardous industrial waste management is limited. The 1996 Safe

Drinking Water Act (SDWA) Amendments, however, establish a new emphasis on preventing contamination problems

through source water protection. Within 18 months after EPA publishes guidance, states must submit a program for

delineating source water areas of public water systems and for assessing the susceptibility of such source waters

to contamination. Because SDWA MCLs have been established for a number for TC and non-TC constituents that are

related to potential gaps, the SDWA could be used under such source water protection programs to regulate

contaminants prior to their entry into public water systems, such as at non-hazardous industrial waste management
Page 9-8

units. The constituents and possible gaps that the SDWA could address under source water protection programs are

discussed below. At this point in time, however, no such source protection programs have been developed.

In Chapter 3, groundwater risks associated with TC analytes were identified as a potential gap in the

hazardous characteristics. As Exhibit 9-4 shows, MCLs are established for 27 of the TC constituents, including

all TC metals with the exception of silver. The seven TC metals with established MCLs are among the top 20

frequently occurring constituents in the release descriptions. MCLs are also established for other constituents

frequently occurring in the release descriptions including chlorobenzene, chloroform, tetrachloroethylene,

trichloroethylene, and vinyl chloride. The MCLs for chlorobenzene, lead, and mercury may address the ecological

risks posed by these constituents, even though EPA did not specifically evaluate ecological risks when setting the

MCLs.

Exhibit 9-4

TC Constituents with SDWA MCL Levels

TC Analyte SDWA MCL TC Analyte SDWA MCL TC Analyte SDWA MCL

1,1-Dichloroethylene -- Chloroform Methyl ethyl ketone --

1,2-Dichloroethane Chromium Nitrobenzene --

1,4-Dichlorobenzene Cresol (mixed isomers) -- o-Cresol --

2,4,5-Trichlorophenol -- Endrin p-Cresol --

2,4,6-Trichlorophenol -- Heptachlor Pentachlorophenol

2,4-D, salts and esters Heptachlor epoxide Pyridine --

2,4-Dinitrotoluene -- Hexachlorobenzene Selenium

Arsenic Hexachloro-1,3-butadiene -- Silver --

Barium Hexachloroethane -- Silvex (2,4,5-TP)

Benzene Lead Tetrachloroethylene

Cadmium Lindane Toxaphene

Carbon Tetrachloride m-Cresol -- Trichloroethylene

Chlordane Mercury Vinyl chloride

Chlorobenzene Methoxychlor

Chapter 4 identified two groups of known non-hazardous industrial waste constituents that may present

hazards through the groundwater pathway: toxic metals and volatile chlorinated organic compounds. Exhibit 9-5

lists chemicals representative of these gaps and indicates whether they have MCLs and were detected above MCL

levels in the release descriptions presented in Chapter 2. In the release descriptions, most of these

constituents were detected in groundwater at levels above their MCLs.
Page 9-9

Exhibit 9-5

MCLs for Known Non-Hazardous Industrial Waste Constituents of Concern

in Groundwater Pathways

Metals MCL MCL Volatile Chlorinated Organics MCL MCL

Detected above Detected above

Aluminum (fume or dust) -- -- 1,1,1,2-Tetrachloroethane -- --

Antimony 1,1,1-Trichloroethane --

Beryllium 1,1,2,2-Tetrachloroethane -- --

Chromium(VI) -- -- 1,1,2-Trichloroethane

Cobalt -- -- 1,2,3-Trichloropropane -- --

Copper -- -- 1,2,4,5-Tetrachlorobenzene -- --

Iron -- -- 1,2,4-Trichlorobenzene --

Magnesium -- -- 1,2-Dibromo-3-chloropropane --

Manganese -- -- 1,2-Dichlorobenzene --

Molybdenum -- -- 1,2-Dichloroethylene -- --

Nickel 1,2-Dichloroethylene, trans

Strontium -- -- 1,2-Dichloropropane --

Thallium 1,3-Dichlorobenzene -- --

Tin -- -- 1,3-Dichloropropylene -- --

Titanium -- -- Allyl chloride -- --

Vanadium -- -- Benzoic trichloride -- --

Zinc -- -- Bis(2-chloroethyl) ether -- --

Chlorobromomethane -- --

Chlorodibromomethane --

Chloroethane -- --

Chloromethane -- --

cis-1,2-Dichloroethylene

Dichloro-2-propanol 1,3- -- --

Dichlorobromomethane --

Dichlorodifluoromethane -- --

Dichloromethane

Dichloropropane -- --

Epichlorohydrin --

Ethylidene Dichloride -- --

Hexachlorocyclopentadiene --

Pentachloroethane -- --

Tetrachloroethane, N.O.S. -- --

trans-1,3-Dichloropropene -- --

Trichlorofluoromethane -- --

Trichloromethanethiol -- --
Page 9-10

9.2.3 Clean Air Act Amendments

Section 112 of the Clean Air Act Amendments (CAAA) regulates emissions of 189 toxic constituents, or

hazardous air pollutants (HAPs). EPA has defined source categories that emit these HAPs and specified the maximum

available control technology (MACT) that must be used by these sources to reduce HAP releases. EPA has promulgated

air toxics regulations for three source categories that handle solid waste: RCRA Subtitle C facilities, off-site

waste operations, and municipal waste combustors. Of these three categories, only off-site waste operations

handle non-hazardous industrial waste.

Off-site waste operations are defined to include hazardous waste treatment, storage, and disposal

facilities, industrial wastewater treatment facilities, industrial waste landfills that receive waste from offsite, and other facilities that provide waste management support services or recover and/or recycle spent

materials. Municipal waste landfills, POTWs, incinerator units, and site remediation activities are not

regulated by this rule. Off-site operations must control emissions from tanks and containers that manage material

with an average volatile organic compound (VOC) concentration equal to or greater than 100 parts per million by

weight. Land disposal of such wastes is prohibited. In addition, a leak detection and repair program must be

implemented for all equipment containing material with total VOC concentration of 10 percent or more. Thus, the

CAA regulations for these sources could address potential gaps in the hazardous waste characteristics in two ways:

Exposures to waste constituents through inhalation are addressed for non-hazardous

industrial wastes with average VOC content greater than 100 ppm, if managed in certain

facilities; and

Exposure to VOCs at off-site operations through direct contact with solid waste or from

groundwater leachate may be reduced or controlled by the prohibition of land disposal of

wastes that contain material with an average VOC concentration equal to or greater than

100 parts per million by weight.

The CAA has the potential to address inhalation exposures from the TC constituents. As Exhibit 9-6

demonstrates, all but seven TC constituents (counting heptachlor expoxide) are designated as HAPs under the CAA.

Inhalation pathway exposure to non-TC volatile chlorinated organic compounds and to persistent organic

pesticides were identified in Chapter 4 as a potential gap in the hazardous waste characteristics. As Exhibit 9-7

demonstrates, the CAA regulates emissions of 16 of the 35 known non-hazardous volatile chlorinated organics. EPA

also has designated as HAPs two of the six persistent pesticides identified in the second column of Exhibit 4-11.

Like the CWA, the CAA specifies emission limits for selected industries. Thus, for a potential gap to be

addressed by the CAA, the gap constituents must be generated by one of the industrial categories regulated by the

CAA. Exhibit 9-8 demonstrates that little overlap exists between the industries subject to CAA air toxics

emission limits and those industries represented in the release descriptions. Among the industries represented in

the release descriptions, the CAA specifies emission limits for segments of the chemicals production industry and

off-site waste management operations. 
Page 9-11

Exhibit 9-6

TC Constituents Designated as HAPs under CAA

TC Analyte CAA HAP TC Analyte CAA HAP TC Analyte HAP

CAA

1,1-Dichloroethylene -- Chloroform Methyl ethyl ketone

1,2-Dichloroethane Chromium Nitrobenzene

1,4-Dichlorobenzene Cresol (mixed isomers) o-Cresol

2,4,5-Trichlorophenol Endrin -- p-Cresol

2,4,6-Trichlorophenol Heptachlor Pentachlorophenol

2,4-D, salts and esters Heptachlor epoxide -- Pyridine --

2,4-Dinitrotoluene Hexachlorobenzene Selenium

Arsenic Hexachloro-1,3-butadiene Silver --

Barium -- Hexachloroethane Silvex (2,4,5-TP) --

Benzene Lead Tetrachloroethylene

Cadmium Lindane Toxaphene

Carbon tetrachloride m-Cresol Trichloroethylene

Chlordane Mercury Vinyl chloride

Chlorobenzene Methoxychlor
Page 9-12

Exhibit 9-7

CAA Hazardous Air Pollutants (HAPs) Specified for Potential Gap Constituents

Volatile Chlorinated Organics CAA HAP Persistent Organic Pesticides CAA HAP

1,1,1,2-Tetrachloroethane -- Aldrin --

1,1,1-Trichloroethane DDD --

1,1,2,2-Tetrachloroethane DDE

1,1,2-Trichloroethane DDT --

1,2,3-Trichloropropane -- Dieldrin --

1,2,4,5-Tetrachlorobenzene -- Hexachlorobenzene

1,2,4-Trichlorobenzene

1,2-Dibromo-3-chloropropane

1,2-Dichlorobenzene --

1,2-Dichloroethylene --

1,2-Dichloroethylene, trans --

1,2-Dichloropropane

1,3-Dichlorobenzene --

1,3-Dichloropropylene

Allyl chloride

Benzoic trichloride

Bis(2-chloroethyl) ether

Chlorobromomethane --

Chlorodibromomethane --

Chloroethane

Chloromethane

cis-1,2-Dichloroethylene --

Dichloro-2-propanol, 1,3- --

Dichlorobromomethane --

Dichlorodifluoromethane --

Dichloromethane

Dichloropropane --

Epichlorohydrin

Ethylidene Dichloride

Hexachlorocyclopentadiene

Pentachloroethane --

Tetrachloroethane, N.O.S. --

trans-1,3-Dichloropropene --

Trichlorofluoromethane --

Trichloromethanethiol --

Emissions standards have not yet been established for the paper, food, primary metals, or non-metallic minerals

industries. As presented in Exhibit 9-8, however, the most important industry in terms of the potential gaps that

the CAA may address is the organic chemicals manufacturing industry. Emissions standards have been established

for segments of this industry.
Page 9-13

Exhibit 9-8

CAA Coverage of Industries Represented in Release Descriptions

Industry Group SIC Code Releases CAA Air Emission Limits

Number of

Documented

Electric, Gas, and Sanitary 49 35 Off-site waste operations, hazardous waste TSDFs

Services (refuse only)

Paper and Allied Products 26 27 no

Chemicals and Allied Products 28 11 Emissions from synthetic organic chemical

industry, elastomer production, epichlorohydrin

production

Food and Kindred Products 20 10 no

Primary Metals 33 6 no

Non-Metallic Minerals 14 4 no

9.3 Federal Insecticide, Fungicide, and Rodenticide Act

FIFRA controls chemical pesticides through a process whereby the manufacturer registers the composition

of the pesticide and certifies to EPA that the pesticide will perform its intended function without unreasonable

adverse impacts in the environment under commonly recognized practices for use. EPA can place a registered

substance under special review if the substance is suspected of causing unreasonable adverse effects on the

environment. Under this process, EPA can prohibit the distribution, sale, and/or use of a pesticide through a

cancellation or suspension of its registration.

Four TC constituents found in the release descriptions are FIFRA active ingredients: 2,4-D, heptachlor,

methoxychlor, and pentachlorophenol. Because FIFRA only places conditions on use, and does not set concentrationbased regulatory levels or regulate pesticide waste disposal, the regulation of these constituents by FIFRA does

not automatically imply that releases will not exceed a certain level. FIFRA could only prevent releases of these

constituents if EPA were to cancel or suspend the respective registrations.

Exhibit 9-9 lists the pesticides, intermediates, and degradation products that are TC analytes or known

non-hazardous industrial waste constituents and the current status of the pesticide. Of the 41 pesticides and

associated products that are known non-hazardous industrial waste constituents, 25 are currently in use and 16 are

cancelled or are not currently used. Several of these pesticides passed the multiple toxicity, persistence,

volatility, and bioaccumulation screening criteria presented in Exhibit 4-13, including aldrin, DDT, DDD, DDE,

dieldrin, heptachlor epoxide, and hexachlorobenzene. With the exception of heptachlor epoxide, these pesticides

have been canceled by EPA. The presense of many of these canceled pesticides as known non-hazardous industrial

waste may largely be the result of old data. For example, the release descriptions, which were used to identify

known constituents, cover waste management units that may have received wastes more than a decade ago.
Page 9-14

Exhibit 9-9

Status of Pesticides That are TC Analytes

or Known Non-Hazardous Industrial Waste Constituents

Pesticides/Intermediate/Degradation Product Status

Aldicarb Active; restricted use

Atrazine Active; restricted use

Carbofuran Active; restricted use

2,4-D, salts and esters Active

Diazinon Active

Dimethoate Active

Disulfoton Active; restricted use

Endosulfan (pesticide is a mixture of alpha and beta isomers) Active

Endosulfan, alpha- Active

Endosulfan, beta- Active

Endosulfan sulfate Metabolic product of endosulfan

Endothall Active

Heptachlor Active; restricted use

Heptachlor epoxide Degradation product of heptachlor

Lindane (gamma-HCH) Active; restricted use

Molinate Active

Mesitylene Active use (registration not required)

Methyl iodide Active use (registration not required)

Methoxychlor Active

Methyl parathion Active; restricted use

O,O-Diethyl O-pyrazinyl phosphorothioate (Thionazin) Active

Parathion Active; restricted use

Pentachlorophenol Active; restricted use

Phorate Active; restricted use

Sulfotepp Active

2,3,4,6-Tetrachlorophenol Canceled

2,4,5-Trichlorophenol Canceled

2,4,6-Trichlorophenol Canceled

Aldrin Canceled

alpha-HCH Canceled

beta-HCH Canceled; no longer produced in U.S.

DDE Degradation product of canceled ingredient

DDT/DDD Canceled

Dieldrin Canceled

Endrin Canceled

Endrin aldehyde Byproduct/degradation product of endrin

Endrin ketone Byproduct/degradation product of endrin

Famphur Most uses canceled; no currently active products

Hexachlorobenzene Canceled

Silvex (2,4,5-TP) Canceled

Toxaphene Most uses canceled; no currently active products

Sources: Farm Chemicals Handbook '94, Meister Publishing Company; U.S. EPA/OPP Database of Pesticide Products, October 8, 1996,

http://www.cdpr.ca.gov/docs/epa/epamenu.htm; Status of Pesticides in Reregistration and Special Review (Rainbow Report),

Office of Pesticides and Prevention, U.S. EPA, June 1994; Merck Index, 12th edition, 1996.
Page 9-15

9.4 Toxic Substance Control Act

TSCA was enacted to fill gaps in the Federal Government's authority to regulate problem chemicals. Most

EPA regulations, such as the Clean Air Act and the Clean Water Act, regulate chemicals only after they are produced

and used. However, there are many opportunities for a chemical to cause harm to human health or the environment

prior to it becoming a waste, such as during production or use. Under Section 6 of TSCA, EPA has the authority to

regulate the production, use, distribution, and disposal of chemicals that are identified as potentially

hazardous. EPA has exercised the authority under Section 6 to regulate the production, distribution, and disposal

of PCBs from electrical equipment and as byproducts of chemical manufacturing processes. The presence of PCBs in

the release descriptions probably results from the past disposal of old products containing PCBs. Because TSCA

bans the production of PCBs, however, their presence in waste should diminish over time. Actions under TSCA do not

significantly address any other potential gaps.

9.5 Pollution Prevention

EPA has developed a number of pollution prevention initiatives that could address potential gaps in the

characteristics by limiting the production of harmful chemicals. These initiatives include:

Source Reduction Review Project (SRRP). EPA has an on-going effort to introduce source

reduction concepts into individual rules. As part of the SRRP, EPA conducted an indepth analysis of source reduction measures and cross-media issues in the development of

24 rule makings for air toxics (Maximum Achievable Control Technology or MACT

standards), water pollution (effluent guidelines) and hazardous wastes (listing

determinations) that were pending in 1993 and 1994. The project's goal is to foster the

use of source reduction measures as the preferred approach for achieving environmental

protection, followed in descending order by recycling, treatment, and as a last resort,

disposal. For the long term, EPA hopes that SRRP will provide a model for the regulatory

development efforts in all of its programs.

Environmental Technical Initiative (ETI). EPA has promoted pollution prevention

efforts for selected industries through technology development. For example, the

Agency has supported research on recycling plastics, replacing current solvents with

less harmful alternatives, and developing cleaner processes in plating and metal

finishing.

Waste Exchanges. Waste exchanges provide a mechanism for recycling and reusing

industrial waste. In general, waste exchanges try to match generators of waste with

companies interested in recycling or reusing these materials. The goals of waste

exchanges are to reduce disposal costs, reduce disposal quantities, reduce demand for

natural resources, and potentially increase the value of wastes. EPA has supported the

non-federal waste exchanges through (1) funding a national computerized listing system,

the National Materials Exchange Network (NMEN), and (2) issuing grants to develop

support for individual waste exchanges or specific waste exchange activities.

Toxics Release Inventory (TRI). The TRI can have an instrumental role in pollution

prevention by providing communities with the information that can be used to persuade

industries to reduce emissions, and by establishing a benchmark to measure progress. 

For example, EPA established the 33/50 Program whereby companies voluntarily pledged to

reduce releases of 17 priority pollutants reported in TRI in 1988 by 33 percent in 1992

and by 50 percent in 1995.
 A PEL is the average maximum concentration of a chemical in air that is allowable for a worker to be exposed to in the course of

2

an 8-hour working day.

Page 9-16

Further research is needed to determine the impact of these initiatives on potential gaps in the characteristics.

9.6 Occupational Safety and Health Act

Workplace safety is largely regulated by the Occupational Safety and Health Act (OSHA). The program that

most directly relates to chemical hazards encountered in the workplace is the permissible exposure limits (PELs)2

established for selected workplace chemicals.

Subpart Z of 29 CFR 1910.1000 specifies PELs for toxic and hazardous substances in the workplace. These

PELs are based on threshold limits values (TLVs) established by the American Conference of Governmental Industrial

Hygienists (ACGIH) and on the Recommended Exposure Limits (RELs) developed by the National Institute for

Occupation Safety and Health (NIOSH). OSHA has adjusted some of these values when developing PELs. The PELs are

intended to reduce diseases such as liver and kidney pains, neuropathy and cardiovascular effects, respiratory

effects, deterioration of lung function, narcosis, biochemical and metabolic changes, and other health

impairments caused by workplace exposure to chemicals.

As discussed above, OSHA regulates workplace inhalation exposure to designated constituents by

establishing PELs. As shown in Exhibit 9-10, 33, or over 75 percent, of the TC constituents have PELs established

under OSHA.

The majority of potential gaps associated with non-TC analytes identified in Chapter 4 are related to

exposures to contaminated media, rather than workplace exposures. OSHA PELs, however, could address workplace

exposures to a few of the major chemicals classes that comprise several of the potential gaps, including volatile

chlorinated organics, other volatile and semivolatile organics, and pesticides. Exhibit 9-11 demonstrates that

21 of the 35 known non-hazardous volatile chlorinated organics in Exhibit 4-2 have OSHA PELs. Similarly, 33 of the

41 and 20 of the 45 other volatile and semivolatile organics, respectively, have OSHA PELs.

9.7 Hazardous Materials Transportation Act

HMTA gives the Department of Transportation (DOT) the authority to regulate the transportation of

hazardous materials in interstate commerce. The HMTA regulates materials not covered by the hazardous waste

characteristic, and therefore addresses hazards from these potential gaps, but only in the context of risks in

transportation and to transportation workers. These materials include the following:
Page 9-17

Exhibit 9-10

TC Constituents with Established OSHA PELs

TC Analyte OSHA PEL TC Analyte OSHA PEL TC Analyte OSHA PEL

1,1-Dichloroethylene -- Chloroform Methyl ethyl ketone

1,2-Dichloroethane Chromium Nitrobenzene

1,4-Dichlorobenzene Cresol (mixed isomers) o-Cresol --

2,4,5-Trichlorophenol -- Endrin p-Cresol

2,4,6-Trichlorophenol -- Heptachlor Pentachlorophenol

2,4-D, salts and esters Heptachlor Epoxide -- Pyridine

2,4-Dinitrotoluene Hexachlorobenzene -- Selenium

Arsenic Hexachloro-1,3- Silver

butadiene

Barium Hexachloroethane Silvex (2,4,5-TP) --

Benzene Lead Tetrachloroethylene

Cadmium Lindane Toxaphene

Carbon Tetrachloride m-Cresol -- Trichloroethylene

Chlordane Mercury Vinyl Chloride

Chlorobenzene Methoxychlor
Page 9-18

Exhibit 9-11

OSHA PELs Specified for Known Non-Hazardous Industrial Waste Constituents

Volatile Chlorinated Organics PEL Other Volatile Organics PEL Other Semivolatile Organics PEL

1,1,1,2-Tetrachloroethane -- 1,2-Dibromoethane 1,2-Diphenylhydrazine --

1,1,1-Trichloroethane 1,4-Dioxane 2,3,7,8-TCDD --

1,1,2,2-Tetrachloroethane 2-Ethoxyethanol 2,4-Diaminotoluene --

1,1,2-Trichloroethane 2-Hexanone 2,4-Dichlorophenol --

1,2,3-Trichloropropane 2-Methyllactonitrile -- 2,6-Dinitrotoluene --

1,2,4,5-Tetrachlorobenzene -- 2-Methylpyridine -- 3,3'-Dimethoxybenzidine --

1,2,4-Trichlorobenzene 2-Nitropropane 4-Aminobiphenyl

1,2-Dibromo-3-chloropropane Acetaldehyde 4-Aminopyridine --

1,2-Dichlorobenzene Acetone 5-Nitro-o-toluidine --

1,2-Dichloroethylene Acetonitrile Acetophenone --

1,2-Dichloroethylene, trans -- Acrolein Acrylamide

1,2-Dichloropropane Acrylonitrile Acrylic acid

1,3-Dichlorobenzene -- Allyl alcohol Adipic acid --

1,3-Dichloropropylene Benzenethiol Aniline

Allyl chloride Benzyl alcohol -- Benzal chloride --

Benzoic trichloride -- Bromoform Benzoic acid --

Bis(2-chloroethyl) ether Bromomethane Benzyl chloride

Chlorobromomethane Carbon disulfide Biphenyl

Chlorodibromomethane -- Crotonaldehyde -- Coal tars

Chloroethane Cyclohexanone Creosote --

Chloromethane Dimethyl sulfate Dibenzofuran --

cis-1,2-Dichloroethylene -- Dimethylamine Diphenyl ether

Dichloro-2-propanol, 1,3- -- Ethane, 1,1'-oxybis- Diphenylamine

Dichlorobromomethane -- Ethyl acetate Ethyl dipropylthiocarbamate --

Dichlorodifluoromethane Ethylene glycol Formic acid

Dichloromethane Ethylene oxide m-Dinitrobenzene

Dichloropropane -- Formaldehyde Maleic anhydride

Epichlorohydrin Furan -- Maleic hydrazide --

Ethylidene Dichloride Furfural N-Nitrosodimethylamine

Hexachlorocyclopentadiene Hydrazine N-Nitrosodiphenylamine --

Pentachloroethane -- Isobutyl alcohol Naphthalene

Tetrachloroethane, N.O.S. -- Malononitrile -- Nitrosamine, N.O.S. --

trans-1,3-Dichloropropene -- Methanol O-Chlorotoluene

Trichlorofluoromethane Methyl isobutyl ketone Ortho(2-)Nitroaniline --

Trichloromethanethiol -- Methyl isocyanate p-Chloroaniline --

Methyl mercaptan p-Chlorotoluene --

Methyl methacrylate p-Nitroaniline

Methylene bromide -- Pentachlorobenzene --

n-Butyl alcohol Phenanthrene --

Urethane -- Phthalic acid --

Vinyl acetate Phthalic anhydride

Polychlorinated biphenyls

Resorcinol

Thioacetamide --

Thiram
Page 9-19

Combustible liquids defined under HMTA as liquids with a flash point above 141 F and

below 200 F. Examples include benzonitrile, camphor oil, chlordane, coal tar

distillate, di-isobutyl ketone, ethylene glycol ethers, and fuel oil distillate;

Corrosive solids and liquids;

aqueous flammable liquids (alcohol solutions < 24 percent);

Non-flammable compressed gases and cryogenic liquids; and

Certain materials specifically forbidden under HMTA, including materials likely to polymerize

at a temperature of 130 F or less, or decompose at 122 F or less, with an evolution of a dangerous

amount of heat or gas.

9.8 Summary

Most of the potential gaps identified in Chapters 3 and 4 are media-specific. As a result, media-specific

regulations provide some control over chemical and chemical classes that comprise the potential gaps. In

addition, non-media-specific regulations such as FIFRA and TSCA could address potential gaps associated with

particular chemical classes, such as pesticides and PCBs. Exhibit 9-12 presents a summary of the non-RCRA

statutes and regulatory programs that could address to varying degrees the potential gaps.

Exhibit 9-12

Potential Gaps and Potential Non-RCRA Regulatory Control

Statute or Regulatory

Program Potential Gap Possibly Addressed

Clean Water Act Direct surface water exposure to TC analytes

Indirect pathway exposures to TC analytes involving surface waters

Risks to ecological receptors involving discharges to surface waters

Indirect pathway exposures to phenolic compounds involving surface waters

DNAPL formulation by chlorinated organics

Indirect pathway exposures to PAHs involving surface waters

Safe Drinking Water Act Implementation of 1996 Amendments to CWA has potential to address potential gaps through

groundwater exposures to TC constituents, non-TC metals, and non-TC volatile chlorinated

organics

Clean Air Act Inhalation pathway exposures to volatile chlorinated organics

Inhalation pathway exposures to persistent organic pesticides

FIFRA Endocrine disruption from chlorinated pesticides, phthalate esters

TSCA Risks to humans, ecological receptors from PCBs

OSHA Inhalation exposures to TC analytes in workplace

HMTA Risks posed by gaps in the ICR characteristics
Page 9-20

For a potential gap to be addressed by the CWA or CAA, the gap constituents must both have regulatory

levels established by the programs and be generated by one of the regulated industrial categories. The CWA and CAA

establish limits for about the same number of volatile chlorinated organics. The industrial categories regulated

by the CWA, however, overlap more extensively than those regulated by the CAA with the industries represented in

the release descriptions. Therefore the CWA effluent limitations will be more effective in addressing potential

gaps. Each of the regulations discussed in this chapter do not address all of the known and possible non-hazardous

industrial waste chemicals, and therefore none of the potential gaps are completely addressed by non-RCRA

regulations.
Page 9-21

CHAPTER 9. POTENTIAL FOR GAPS TO BE ADDRESSED BY EXISTING REGULATIONS . . 9-1

9.1 RCRA Programs ......................................................... 9-1

9.1.1 Hazardous Waste Programs ........................................... 9-1

9.1.2 Subtitle D ......................................................... 9-3

9.2 Medium-Specific Regulations .............................................. 9-3

9.2.1 Clean Water Act .................................................... 9-4

9.2.2 Safe Drinking Water Act ............................................. 9-7

9.2.3 Clean Air Act Amendments .......................................... 9-10

9.3 Federal Insecticide, Fungicide, and Rodenticide Act ............................ 9-13

9.4 Toxic Substance Control Act .............................................. 9-15

9.5 Pollution Prevention ..................................................... 9-15

9.6 Occupational Safety and Health Act ........................................ 9-16

9.7 Hazardous Materials Transportation Act ..................................... 9-16

9.8 Summary .............................................................. 9-19
Page 9-22

Exhibit 9-1 TC Constituents with Effluent Limits Established under CWA .................... 9-5

Exhibit 9-2 CWA Effluent Limitations Relevant to Certain Known Non-Hazardous Industrial

Waste Constituents ....................................................... 9-6

Exhibit 9-3 CWA Coverage of Industries Represented in Release Descriptions ................. 9-7

Exhibit 9-4 TC Constituents with SDWA MCL Levels .................................... 9-8

Exhibit 9-5 MCLs for Known Non-Hazardous Industrial Waste Constituents of Concern in

Groundwater Pathways .................................................... 9-9

Exhibit 9-6 TC Constituents Designated as HAPs under CAA ............................. 9-11

Exhibit 9-7 CAA Hazardous Air Pollutants (HAPs) Specified for Potential Gap Constituents .... 9-12

Exhibit 9-8 CAA Coverage of Industries Represented in Release Descriptions ................ 9-13

Exhibit 9-9 Status of Pesticides That are TC Analytes or Known Non-Hazardous Industrial

Waste Constituents ...................................................... 9-14

Exhibit 9-10 TC Constituents with Established OSHA PELs ............................... 9-17

Exhibit 9-11 OSHA PELs Specified for Known Non-Hazardous Industrial Waste Constituents .... 9-18

Exhibit 9-12 Potential Gaps and Potential Non-RCRA Regulatory Control .................... 9-19
Page 10-1

CHAPTER 10. SUMMARY EVALUATION OF NATURE AND

EXTENT OF POTENTIAL GAPS

This chapter evaluates potential gaps in terms of their significance to human health and the environment. 

It synthesizes and summarizes information presented in previous chapters. 

Section 10.1 discusses the objectives of the gaps analysis and the specific criteria used to evaluate

potential gaps.

Section 10.2 presents the findings of the evaluation and discusses major data gaps and unresolved

issues.

Section 10.3 describes a possible framework for determining an appropriate course of action based on the

results of this Scoping Study.

10.1 Overview of the Evaluation of Potential Gaps

10.1.1 Objectives of the Gaps Analysis

Since this Study is a scoping exercise, the human health and environmental impacts of potential gaps have

not been definitively analyzed, and potential gaps are not numerically ranked with regard to their impacts. 

Instead, the Study's objective is to summarize available information in a manner that will be useful in guiding

further, more detailed assessment of the most important potential gaps and their possible solutions. The

categories of gaps are evaluated qualitatively against criteria that address the potential for adverse human

health and environmental impacts.

Many of these criteria have been used in previous chapters to identify and analyze potential gaps. The

analysis presented below, however, differs from previous analyses in two ways. First, while the same data sources

are used, more detailed analyses are presented for key constituents, pathways, and risks. Second, instead of

focusing on individual chemicals, the chapter analyzes groups of chemicals and specific environmental problems. 

This approach helps to generalize the analysis to include chemicals for which limited data are available regarding

appearance in wastes, toxicity, or environmental fate and transport characteristics.

10.1.2 Criteria Used for Evaluating Gaps

Section 10.2 presents a series of exhibits (Exhibits 10-1 through 10-4) comparing the various categories

of potential gaps identified and reviewed in previous chapters. Potential gaps are compared using criteria that

relate to various dimensions of risks to human health and the environment. These criteria, which correspond to

columns in the exhibits, are described below. (Because of data gaps or the inapplicability of some criteria to

certain potential gaps, some exhibits do not include all of these criteria.)

Nature of Risks. This criterion qualitatively characterizes the nature of the risks posed by potential

gaps, including the types of possible injuries or adverse effects, important toxicological effects (e.g.,

carcinogenicity, reproductive effects, or mutagenicity), and fate and transport properties. These factors are

important in evaluating risk potential.
Page 10-2

Presence in Non-Hazardous Industrial Waste. This entry indicates the number of the TC analytes and known

or possible non-hazardous industrial waste constituents identified in Chapter 4 that fall into the potential gap

and summarizes other available data on presence in waste. The number of chemicals in a given class indicates, to

some extent, the potential frequency of their appearance in non-hazardous industrial wastes or use in different

industries.

Frequently Detected Constituents in Release Descriptions. This column indicates how frequently the class

of chemicals was detected in the documented releases from non-hazardous industrial waste management facilities. 

These data provide a second indicator of the frequency of the class of chemicals in wastes released to the

environment. In some tables, this column also addresses the extent to which the releases had constituent

concentrations detected in excess of health- or ecologically-based regulatory standards or other health-based

levels. These data address the severity and type of the risk presented by the releases.

TRI Chemicals with Releases > One Million Pounds. This column identifies any constituents falling into

the identified potential gaps that have 1994 TRI releases to air, land, water, and underground injection combined

greater than one million pounds. Eighty-three of the 250 individual or classes of TRI chemicals for which data

were available had reported releases exceeding one million pounds. These data served as a proxy for widespread use

and appearance in wastes.

Affected Industries. This column presents two types of data. First, it identifies the industries most

often associated with documented releases of a particular class of chemicals in the release descriptions. These

data indicate, at least for the population of facilities evaluated, which industries seem to have the highest

frequency of releases to the environment of each class of compounds. As noted previously, however, this indicator

is imperfect, in part because the available data focus on releases to groundwater and some families of

constituents may present risks primarily through other pathways. The column also uses information presented in

Chapter 8 to identify the industries with particular classes of chemicals frequently occurring in their nonhazardous industrial wastes.

Affected Management Methods. This column identifies the types of management units at which the various

classes of chemicals are detected most frequently in the release descriptions or other data sources. This

criterion has the same limitation as the release description information identified above, namely, it focuses on

groundwater contamination and thereby may miss chemicals that pose risks through other pathways. However, since

presence in groundwater indicates presence in wastes, this column also provides information about the types of

management units or practices that have releases to groundwater and are likely to have releases to other media

(e.g., volatilization), as discussed in the screening-level risk results from Section 3.5.

Potential Coverage by Other Regulations. This column summarizes information presented in Chapter 5 (for

large-scale environmental problems) and Chapter 9 (for TC and non-TC chemicals). It briefly describes the

potential extent of coverage of potential gaps by existing regulatory programs. In some cases, despite the

appearance that a particular gap is covered by a regulatory program, information from the release descriptions or

elsewhere may indicate that such coverage is not preventing releases to the environment.

Comments/Data Gaps. The final column of each table identifies the major analytical uncertainties and

limitations in the characterization of potential hazardous waste characteristics gaps. As noted above, a major

obstacle to identifying gaps accurately and reliably is the shortage of information regarding the generation,

composition, and management of non-hazardous industrial wastes and any human health or environmental damages

resulting from the management of such wastes. Data may be available to fill some of the identified gaps, but, due

to time constraints, these data were not used in preparing this Scoping Study.
Page 10-3

10.2 Findings of the Evaluation

This section summarizes the evaluations of the five different types of potential gaps identified in the

previous chapters, namely potential gaps associated with:

The existing ignitability, corrosivity, and reactivity characteristics;

The existing toxicity characteristic;

Chemicals not included in the toxicity characteristic;

Natural resource damages and large-scale environmental problems; and

State expansion of the TC and listings.

The last part of this section reviews the major data gaps and uncertainties.

10.2.1 Potential Gaps Associated with the ICR Characteristics

Ignitability

Exhibit 10-1 summarizes the analysis of the potential gaps in the ICR characteristics. (This exhibit does

not include a column on the constituents that were frequently detected in the release descriptions because of the

difficulty of judging waste ICR properties based on the environmental monitoring data (e.g., groundwater sampling

from the release descriptions). The first page of the exhibit addresses the limitations in the ignitability

characteristic. The first potential gap in this characteristic relates to the lack of coverage of combustible

liquids, that is, liquids with flash points above 140 F and below 200 F. The Agency has not found any data on how o o

often non-hazardous industrial wastes exhibit this property. While many non-hazardous industrial waste

constituents are flammable, the flash point and fire hazard from a given waste depends on its composition and

management practices. Thus, the high frequency of appearance of flammable liquids among the waste constituents or

groundwater contaminants does not necessarily reflect a high hazard potential. The release descriptions did not

allow EPA to evaluate the frequency of fires and explosions at non-hazardous industrial waste management

facilities, let alone to determine whether any fires had resulted from combustible liquids.

Dilute aqueous solutions of alcohol also are identified as a potential gap in the ignitability

characteristic. These solutions might flash, even if they are not capable of sustaining combustion. Ethanol,

however, is not a known or possible non-hazardous industrial waste constituent or a TC analyte, suggesting that

this gap may not be significant. Nevertheless, the narrow definition of this characteristic excludes other

organic liquids that can form potentially flammable mixtures with water. The possible limitations of this narrow

definition are illustrated by the presence among waste constituents of water-miscible alcohols, such as methanol

(with the highest release volume on the TRI list), n-butanol, and isobutanol, as well as other potentially

flammable water-miscible solvents, such as acetone, methylethyl ketone, and acetonitrile.

EPA found no data on the extent of potential hazards from ignitable solids. Thus, the consequences of not

having a test method for these materials are difficult to characterize. The release
Page 10-4

Exhibit 10-1

Evaluation of Potential Gaps Associated With the Ignitability, Corrosivity, and Reactivity (ICR) Characteristics

Potential Gap Nature of Risk Industrial Waste Million lbs. Affected Industries AffectedManagement Methods Regulations Comments/MajorData Gaps

Presencein Non-Hazardous Reported Releases > One Potential Coverage by Other

TRIChemicals with 1994

IGNITABILITY Fires under plausible Some proportion of N-butyl alcohol, MIBK, Wide range of indus- Hazards may be most Variety of local, state, Flash point of waste

 Exclusion of DOT

Combustible Liquids

(flash point between

140 F and 200 F) o o

mismanagement scenarios wastestreams are likely to acetonitrile, ethylene tries produce relevant for waste handling and federal laws address depends on various factors

be combustible, but are not glycol, acetaldehyde combustible materials activities such as ignitable hazards, includ- including concentrations of

readily identifiable with including chemicals, generation, storage, and ing constituents.

existing data. petroleum refining, transportation. -- DOT transportation Difficult to identify

 Combustible materials asphalt materials and Landfills more likely to rules; potentially affected

include certain alcohols, paving be of potential concern than -- Fire codes; wastestreams in the absence

low molecular weight ethers, Industries using surface impoundments -- Emergency prevention of flash point data for

kerosene, jet fuels, paints, adhesives, inks, because surface and preparedness under specific wastestreams

petroleum byproducts, tints and fuels impoundments dilute wastes EPCRA, OSHA, and CAA No data available on

and paints, and others. and thereby reduce §112(r); and fires from combustible

ignitability; flammable -- State Industrial D rules liquids

organic liquids are not limiting landfilling of

likely to be managed in liquids.

impoundments.

 Exclusion of These liquids could Many constituents could Methanol, n-butanol, Chemicals, refuse DOT has a similar

Aqueous Flammable flash, even if combustion form flammable mixtures withiso-butanol, ethylene services exclusion.

Liquids (alcohol is not sustained. water. glycol, acetonitrile, No data available on

solutions < 24 MIBK, acetaldehyde fires from these liquids

percent)

 References Outdated Confusion regarding Not applicable Not applicable Not applicable No data available on

DOT Regulations definition and test fires due to improper

methods due to incorrect testing or failures to test

DOT citation

 No Ignitability More difficult to Could include soils and Not addressed Not addressed Potential gap is diffiTest Method for Non- interpret, comply with, sorbents contaminated with cult to characterize.

liquids and enforce regulations. ignitable materials DOT and NFPA have defined

test methods for flammable

solids.
Exhibit 10-1 (continued)

Evaluation of Potential Gaps Associated With the Ignitability, Corrosivity, and Reactivity (ICR) Characteristics

Potential Gap Nature of Risk Industrial Waste Million lbs. Affected Industries AffectedManagement Methods Regulations Comments/MajorData Gaps

Presencein Non-Hazardous Reported Releases > One Potential Coverage by Other

TRIChemicals with 1994

Page 10-5

CORROSIVITY Skin, eye injuries and Not addressed Not addressed Not addressed Not addressed Several states regulate Lack of data on specific

 Exclusion of

Corrosive Non-liquids

ecological risks, corrosive solids as substances, wastes, and/or

facilitated transport of hazardous waste. damage cases that fall

pollutants within potential gaps.

 pH Limits Poten- pH test may not Not addressed Not addressed Not addressed DOT and OSHA rules use a

tially Not Protective, identify some corrosive dermal corrosion test (not

pH Test Methods Not materials pH); they cover worker and

Predictive of Risk transportation risks.

 Corrosion of Non- Corrosion of plastic, Many NAPL-formers; Toluene, xylene, carbon Waste management methods CAA limits disposal of

Steel Materials Not clay, other liner alcohols, ketones disulfide, styrene, that involve materials such solvents in certain units.

Addressed materials and non-steel ethylbeneze, as plastic, clay, and other

containers or tanks trichlorofluoromethane, materials besides steel

phenols (as group),

various alcohols

 Solubilization of Organic solvents may Many potential LNAPL or Toluene, xylene, carbon Waste management methods CAA limits disposal of

Non-Metals Not solubilize organic DNAPL forming constituentsdisulfide, styrene, with potential for discharge solvents in certain units.

Addressed constituents could solubilize other ethylbeneze, to water bodies or other

organics. trichlorofluoromethane, habitats

phenols (as group)

 Exclusion of Allergic reaction in Numerous chemicals Ammonia, formaldehyde, Waste handling situations OSHA hazard communication

Irritants and waste management and including ammonia, copper, (of those listed in where spills could occur standard covers irritants

Sensitizers transportation workers beryllium, cobalt, copper, prior column) and sensitizers, which

 Unclear whether this nickel, carbonyl, affords protection to

hazard meets RCRA formaldehyde, isobutyl employees at wide range of

Subtitle C statutory alcohol, n-Dioctyl facilities (e.g.,

level of concern phthalate, benzoic acid, and generating facilities,

coal tars waste management

facilities)
Exhibit 10-1 (continued)

Evaluation of Potential Gaps Associated With the Ignitability, Corrosivity, and Reactivity (ICR) Characteristics

Potential Gap Nature of Risk Industrial Waste Million lbs. Affected Industries AffectedManagement Methods Regulations Comments/MajorData Gaps

Presencein Non-Hazardous Reported Releases > One Potential Coverage by Other

TRIChemicals with 1994

Page 10-6

REACTIVITY Ambiguity may allow Many constituents are Ammonia, hydrochloric Not addressed Not addressed Explosions and other Potential gap is diffi-

 Broad, Non-Specific

Definition

substances posing risks DOT-reactive, none are acid, phosphoric acid, related hazards covered by cult to characterize

of gas generation or identified as "highly nitric acid, sulfuric programs including fire and because reactive wastes are

violent reaction to be reactive". acid, hydrogen fluoride, building codes, DOT already regulated as

managed improperly. hydrogen cyanide, chlorine regulations (for hazardous

dioxide transportation only), OSHA

regulations, and accident

prevention and preparedness

regulations under EPCRA and

CAA §112(r)

 References Outdated Confusion about

DOT Regulations relevant standards may 

reduce compliance and

increase risks of violent

reactions.

 No Test Methods More difficult to

Specified interpret, comply with,

and enforce regulations
 "Fluorides/fluorine/hydrogen" (the slashes indicate that the exact chemical species is not identified) are among the frequently 1

detected constituents, but these detections most probably refer to fluoride ion, rather than to the acid.

Page 10-7

descriptions do not, as noted above, identify any fires related to flammable solids. Also, as noted in Chapter 3,

various data searches failed to identify any incidents that could be unambiguously related to flammable solids in

non-hazardous industrial waste management units. At least one potential variety of flammable solids, soils

contaminated with petroleum byproducts, are explicitly excluded by statute from RCRA Subtitle C jurisdiction.

Finally, the test methods referenced in the ignitability characteristic are outdated and need to be

revised. The U.S. Department of Transportation has promulgated new methods in different sections of the Code of

Federal Regulations. EPA, however, is not aware of any fires or other adverse events arising from confusion over

the proper test methods.

Corrosivity

The second panel in Exhibit 10-1 addresses potential gaps in the corrosivity characteristic. Several

potentially corrosive substances, primarily strong acids, are identified among the known and possible nonhazardous industrial waste constituents. These compounds are not among the most frequently detected groundwater

contaminants in the release descriptions, however. No information is available concerning corrosive non-liquids 1

in the release descriptions.

A potential gap associated with the pH range of the corrosivity characteristic also was identified. The

release descriptions identify decreased or elevated pH levels in groundwater near management units for a number of

the industries. While the reported pH levels are not associated with skin or eye injury or injury to biota, the

appearance of elevated or depressed pH in groundwater after dilution indicates that high- and low-pH wastes are

frequently encountered among the non-hazardous industrial wastes. The extent to which the pH of these wastes

falls into the potential gap between the existing pH limits in the corrosivity characteristic and possible more

stringent limits is not known, however.

The corrosivity characteristic also does not address corrosion of materials other than steel. 

Specifically, the Agency has identified potential corrosion of plastics and clay (common materials used in liners

of non-hazardous industrial waste management units) as a potential gap. For example, the plastic liners may be

corroded by nonaqueous phase liquids (NAPLs) if present in significant amounts; as is discussed in more detail in

Section 4.2.3, a number of TC analytes and known and possible waste non-hazardous industrial constituents could

form NAPLs. In addition, certain ketones and alcohols could dehydrate or otherwise adversely affect the physical

integrity of clay liners.

Finally, the corrosivity characteristic excludes irritants and sensitizers. The Agency has found a

number of allergic sensitizers to be constituents of non-hazardous industrial wastes, including ammonia,

beryllium, cobalt, copper, nickel, nickel carbonyl, formaldehyde, isobutyl alcohol, n-dioctyl phthalate, benzoic

acid, and coal tars. Further analysis may identify other substances. While the release descriptions do not report

any incidents of allergic sensitization, dermatitis is one of the most common occupational illnesses, and nonhazardous industrial waste could contribute to these potential risks to waste management and transportation

workers. Occupational Safety and Health Act regulations prescribe measures to limit dermal exposures to hazardous

substances in the workplace, however. Thus, this problem is at least partially addressed by non-RCRA regulations.

Reactivity
Page 10-8

The final panel of Exhibit 10-1 summarizes the information related to the potential gaps in the reactivity

characteristic. A major question for this potential gap is whether the over-broadness of the definition has

increased the occurrence of human health or environmental damages or risks due to reactive materials. The release

descriptions do not contain information related to violent chemical reactions. Also, while some DOT-classified

reactive chemicals are among the non-hazardous industrial waste constituents, there is no evidence that would

indicate whether these chemicals are present in forms or concentrations that are reactive. The need to specify

test methods is likewise linked both to the severity of reactivity as a problem for non-hazardous industrial waste

management operations, and to the extent to which such issues are not already addressed by the DOT regulations,

OSHA regulations, or process safety management practices.

10.2.2 Potential Gaps Associated with TC Analytes

Exhibit 10-2 summarizes the analysis of five types of potential gaps associated with the toxicity

characteristic:

TC regulatory levels for the groundwater pathway;

Risks through non-groundwater pathways, including inhalation, surface water, and indirect

pathways;

Acute human health risks;

Risks to ecological receptors; and

Limitations in the TCLP.

Each of these gaps is discussed below, following a brief review of data applicable to all four potential gaps.

One indication of the significance of these potential gaps is that 25 of the 40 TC analytes were detected

in at least one of the descriptions of releases from non-hazardous industrial waste management units described in

Chapter 2. Many are detected frequently above regulatory levels. Six TC metals and arsenic are among the most

commonly detected analytes in the release descriptions.

All TC analytes are regulated under federal and state regulatory schemes in addition to the RCRA hazardous

waste characteristics. The TC analytes are included in 40 CFR Part 261, Appendix VIII, and therefore many wastes

have been listed based on the presence of TC chemicals. Media-specific regulatory programs also control

individual analytes. MCLs or MCLGs have been promulgated to limit exposures to about half the TC analytes in

community drinking water systems. Most volatile TC analytes are Hazardous Air Pollutants under the CAA, and most

TC analytes have OSHA Permissible Exposure Limits (PELs), which limit occupational exposures. CWA Ambient Water

Quality Criteria trigger regulatory control of most of the TC analytes through NPDES permits and state surface

water quality standards, although, as noted in Chapter 3, the TC regulatory levels may not be adequately

protective against surface water risks for some analytes.
Page 10-9

Exhibit 10-2

Evaluation of Potential Gaps Associated with Toxicity Characteristic Analytes and TCLP

Potential Gap Nature of Risk Descriptions lion lbs. Affected Industries Methods Regulations Comments/Major Data Gaps

Detection in Release Reported Releases > Mil- Affected Management Coverage by Other

TRI Chemicals with 1994

Groundwater pathway risks Wastes with TC constituents below 7 TC metals (lead, Methyl ethyl ketone, Industries with Landfills, surface RCRA listings, state Variability and

from wastes below TC regulatory levels may pose chronic chromium, arsenic, cadmium,trichloroethylene, frequent detections of impoundments, land Industrial D, SDWA uncertainty in calculated

regulatory levels health cancer risk >10 , noncancer barium, mercury, selenium) chromium compounds, metals in release application units, DAF values, depending on

 Uniform DAF value hazard quotient > 1 in nearby populationsare among top 20 frequently lead compounds, chloro- descriptions include waste piles, poten- modeling assumptions

potentially not exposed through groundwater ingestion. detected constituents. form, tetrachloro- chemicals, paper, tially others Limited non-hazardous

protective for some TC Other TC constituents ethylene, benzene, 1,2- refuse systems, industrial wastestream data

constituents. occurring > 5 times are ben- dichloroethane, industrial sand,

-5

zene, trichloroethylene, chromium, arsenic and primary metals, and

vinyl chloride, silver, compounds, others.

chlorobenzene, chloroform, chlorobenzene, vinyl

and tetrachloroethylene. chloride

Inhalation risks were not For 16 TC organics with inhalation cancer Vinyl chloride, Methyl ethyl ketone, Chemicals, refuse Surface impound- RCRA listings, state Most organic analytes

considered in derivation risk data, risk > 10 was found for: chloroform, chlorobenzene, chloroform, 1,2- systems, and others ments, land applica- Industrial D, CWA that exceed inhalation risk

of TC levels. Volatile 0 and 12 analytes in central tendency 1,4-dichlorobenzene and dichloroethane, vinyl tion units, landfills, NPDES, CAA, OSHA PELs thresholds are not very

organics pose such risks. and high-end surface impoundments carbon tetrachloride are chloride and possibly waste persistent in either soil or

-5

respectively; and among most frequently handling water.

 0 and 4 in central tendency and high- detected analytes. Release descriptions did

end LAUs respectively. not identify inhalation

For 4 TC organics with inhalation non- problems.

cancer risk data, HQ > 1 was found for: Limited wastestream data

 3 or 4 of central tendency or high-end

respectively of both surface

impoundments and LAUs.

Surface water risks to Potential chronic health cancer risks Toxic, bioaccumulative Specific constituents Not addressed Surface impound- Intentional Risks may be significant

human health were not >10 , noncancer risks HQ > 1 in nearby constituents of potential of potential concern ments, landfills, land discharges limited by only in narrow range of

considered in the deriva- populations exposed to surface water by concern were not identified were not identified. application units, NPDES; state CWA conditions.

tion of TC levels. consumptive use or recreational use frequently in the release waste piles Industrial D design Limited wastestream data

-5

descriptions. requirements limit Release descriptions

unintentional include few surface water

releases releases.

Indirect/food chain Potential human health risks from Lead, mercury, arsenic, Lead compounds, Industries with Surface impound- RCRA listings, state Limited data on

pathway risks to human consumption of fish, crops, beef/dairy chloroform were frequently chloroform, arsenic frequent detection of ments, land applica- Industrial D, CWA wastestreams, releases to

health were not products detected. compounds metals include tion units, and NPDES, CAA, FIFRA various media, and resulting

considered in derivation Persistent bioaccumulative TC Persistent pesticides chemical, paper, and landfills damages

of TC levels. Persistent analytes are chlorinated pesticides, were not frequently sanitary services.

and bioaccumulative chloroform, hexachloro-1,3-butadiene, detected.

chemicals pose such mercury, arsenic, and lead.

risks.
Exhibit 10-2 (continued)

Evaluation of Potential Gaps Associated with Toxicity Characteristic Analytes and TCLP

Potential Gap Nature of Risk Descriptions lion lbs. Affected Industries Methods Regulations Comments/Major Data Gaps

Detection in Release Reported Releases > Mil- Affected Management Coverage by Other

TRI Chemicals with 1994

Page 10-10

Acute adverse health Screening analysis showed that short- Specific constituents of Specific constituents Not addressed Not addressed. OSHA PELs, CAA Acute hazards are

effects were not term concentrations of all volatile TC potential concern were not of potential concern addressed by ICR

considered in derivation organics calculated at fenceline were identified. were not identified. characteristics

of TC levels. far below applicable short-term (occupational) exposure standards

 Unusual release events (e.g., fires or

explosions) could result in higher exposures

Ecological risks were not Potential damage to nearby aquatic Lead, mercury, silver, and Chlorobenzene Chemicals, refuse Waste piles, land State Industrial D, Uncertainty in estimating

considered in derivation ecosystems from releases to surface chlorobenzene each were systems, paper, application units, CWA effluent limits, degradation and dilution

of TC levels. TC water and through aquatic and possibly detected at more than 5 of primary metals, and surface impoundments, FIFRA Limited data on

constituents include terrestrial food chain exposures from 112 releases. others landfills wastestreams and releases to

potent ecotoxins, runoff various pathways

persistent and TC analytes with a ratio of TC leachate

bioaccumulative concentration to AWQC > 10,000 include

pesticides. chlorinated pesticides, chlorobenzene,

lead, mercury, pentachlorophenol,

silver, toxaphene, and

2,4,5-trichlorophenol.

 Ratio is > 100,000 for mercury,

methoxychlor, silver, and toxaphene.

TCLP may not accurately Release concentrations may be higher Lead, cadmium, chromium, Chromium compounds, Not addressed All types RCRA listings, state Limited data on

predict leachate concen- or lower than predicted, implying higher arsenic, barium, benzene, lead compounds, arsenic Industrial D; states wastestreams and management

tration or risks for or lower exposure concentrations and selenium, lindane, and vinyl compounds, and vinyl have developed alter- unit environments

certain wastes and units. risks. chloride were detected in chloride (of those native leaching proce- Waste heterogeneity,

 Main concerns are for oily wastes; groundwater at levels listed in prior column) dures, e.g., Cal WET sampling procedures, sample

highly alkaline wastes; wastes with exceeding their TC levels, preparation, leaching

multiple constituents; wastes disposed indicating that TCLP may procedure contribute to

in certain types of landfills; some types have underestimated the uncertainty in test results.

of treated wastes; some types of con- long-term releases of some

taminated soil; and non-groundwater wastes.

pathways.
Page 10-11

TC Regulatory Levels for Groundwater

The first of the potential TC gaps concerns whether the existing leachate concentrations remain

demonstrably protective of human health through the groundwater pathway, given advances in toxicological, fate,

and transport data and modeling since the TC was promulgated. As noted in Section 3.5.2, the only changes in

toxicological values that have occurred since the TC was promulgated are the reduction of the RfD for

pentachlorophenol, promulgation of a cancer slope factor for this compound, the reduction in the RfD for p-cresol,

the replacement of the MCL for lead with a lower action level, and replacement of the MCL for silver with an SMCL. 

Of these changes, only the classification of pentachlorophenol as a carcinogen significantly changes the risk

implicit in the TC regulatory levels. EPA also has refined its approach for modeling the fate and transport of both

organic and inorganic constituents in groundwater. Most recently, groundwater risks were modeled for the TC

analytes in the HWIR-Waste proposed rulemaking. This modeling, which is still undergoing revisions, was performed

using some assumptions that differ significantly from those made in the derivation of the TC regulatory levels. 

Nevertheless, the results, which are proposed health-protective exit levels for releases to groundwater, can be

interpreted to imply that some TC regulatory levels may not protect human health to the extent originally

intended. Without more detailed modeling that duplicates, where appropriate, the TC input assumptions, no firm

conclusions can be drawn about which TC regulatory levels do or do not meet the original risk objectives, however.

Risks Through Non-Groundwater Pathways

Another major potential TC gap relates to exposures associated with inhalation, surface water, and

indirect exposure pathways. These pathways were not considered when the TC was promulgated. The results of the

proposed HWIR-Waste modeling also provide evidence that non-groundwater pathway risks may be important for

several TC analytes. For nine of these substances, non-groundwater indirect exposures resulted in the highest

risks and thereby determined the HWIR-Waste proposed exit concentrations. These pathways included both air and

surface water. In most cases, the proposed exit concentrations for the indirect pathways are considerably lower

than those based only on the groundwater pathway. These modeling results provide further evidence that the TC

levels may not be sufficiently protective for some highly toxic, volatile, persistent, and/or bioaccumulative

chemicals when pathways other than groundwater are considered.

The screening-level modeling in Section 3.5.3 identified various TC constituents that may present

inhalation risks when present in wastes at TC regulatory levels. For example, estimated lifetime cancer risks

exceeded 10-5 for 12 of the 16 TC analytes for which EPA has promulgated inhalation Unit Risk values, assuming

management in “high-end” surface impoundments. Cancer risks exceeded 10-5 for 4 of these 16 analytes when

management in a high-end land application unit (LAU) was assumed. None of the analytes posed cancer risks above

this level when managed in “central tendency” units.

The Agency has promulgated inhalation pathway Reference Concentrations for only four TC analytes

(chlorobenzene, methyl ketone, nitrobenzene, and 1,4-dichlorobenzene). When releases were modeled from high-end

impoundments or LAUs, all four analytes had inhalation pathway hazard quotients above 1.0. When the central

tendency impoundments are modeled, three of the four analytes (all but 1,4-dichlorobenzene) still have HQ values

above 1.0.

All the analytes with screening-level risk estimates above levels of potential concern were found in the

release descriptions; several of them occur frequently in the release descriptions. Four of these constituents

are among the chemicals with total TRI release volumes greater than one million pounds, as noted in Exhibit 10-2.

EPA did not perform quantitative risk modeling of surface water and indirect pathways. Instead, the

Agency reviewed the toxicity and fate and transport parameter values for the TC analytes to develop a qualitative
Page 10-12

indication of the potential risks to human health that they might present when managed in Subtitle D units, as

discussed in Section 3.5.4. A substantial proportion of the analytes have properties, such as volatility,

persistence in air, soil, and water, and high bioaccumulation potential, that suggest potential exposure through

surface water or indirect pathways might result in significant risks. The proposed HWIR-Waste modeling results

for indirect pathways discussed above suggest the need for more detailed modeling, using assumptions consistent

with those used to derive the TC regulatory levels, to better determine which indirect pathways are the most

important for which TC analytes.

Acute Adverse Effects

The TC was originally established based on the need to protect individuals from adverse health effects due

to chronic exposures to the TC constituents consumed in groundwater. This approach to protecting against

groundwater exposure risks is conservative because the relatively long time scale generally involved in

groundwater transport to receptors means that limiting concentrations in any time period to the low chronic riskbased levels also will protect against short-term adverse effects. This relationship may not apply to exposure

through pathways not involving slow releases to groundwater. For example, the rapid evaporation of volatile

chemicals from a ruptured container, the catastrophic release due to overtopping of a surface impoundment, or

runoff erosion from an extreme storm event has the potential to result in short-term (acute) exposures to humans

and environmental receptors.

Thus, EPA evaluated the potential for acute adverse effects associated with rapid volatilization of

chemicals from land management units. This screening-level analysis indicated that the short-term concentrations

of all volatile TC analytes calculated at the fenceline were far below applicable short-term exposure standards

(in this case, occupational exposure standards). This simple modeling does not unconditionally eliminate the

possibility of adverse effects from acute exposures to the TC analytes. Unusual release events, such as fires or

explosions, could result in higher exposures than calculated assuming simple volatilization. In addition, high

winds or other events could result in high concentrations of particle-bound metals and other nonvolatile analytes. 

The potential for these kinds of release events strongly depends on specific waste characteristics, site

conditions, and management practices.

Risks to Ecological Receptors

The next potential gap in the TC is its lack of specific consideration of potential adverse effects on

ecological receptors. Section 3.5.7 found that several TC analytes are highly toxic to aquatic biota, which

suggests that this potential gap may be significant. Some of these constituents occur frequently in the release

descriptions. One potent ecological toxicant (chlorobenzene) is among chemicals with TRI releases greater than

one million pounds. Several TC analytes, including the chlorinated pesticides, chlorobenzene, mercury, and

silver have TC levels greater than 1,000 times their respective AWQC, which indicates a risk to aquatic biota value

if dilution after release is less than 1,000-fold. Mercury, methoxychor, silver, and 2,4,5-trichlorophenol have

TC levels more than 10,000 times their AWQCs. In addition, as discussed in more detail in Section 10.2.4, several

TC analytes (cadmium, heptachlor, heptachlor oxide, lead, mercury, methoxychlor, and toxaphene) have been

identified as suspect endocrine disruptors for wildlife, as well as humans. All these lines of evidence support

the importance of this potential gap. Some ameliorating considerations, however, include the relative lack of

evidence for environmental damage in the release descriptions summarized in Chapter 2, and the existing bans

and/or use restrictions on many of the TC pesticides, which comprise most of the potent ecological toxicants.
Page 10-13

TCLP Limitations

 The final potential gap in the TC characteristic is the limitations in the ability of the TCLP to

accurately predict releases of hazardous constituents from wastes. The Agency has received numerous comments and

data on the utility of the TCLP in general and for specific wastes and environments. Potential limitations of the

method include difficulties in performing the analysis on oily, hydrophobic wastes and in simulating leachate

characteristics for highly alkaline wastes, certain types of landfill environments, long-term mobility of

organics in some treated (non-hazardous) wastes, and some contaminated soils. Furthermore, the TCLP was not

designed to simulate releases into non-groundwater pathways (e.g., air).

In the context of this Scoping Study, EPA has not identified any significant new information bearing on

the magnitude of this potential gap. The Agency has reviewed other possible leaching methods (such as the SPLP and

Cal WET methods), but has not found compelling evidence that they are more appropriate for general use than the

TCLP. The high frequency of occurrence of TC analytes in groundwater above MCLs or HBLs near non-hazardous

industrial waste facilities, as shown in the release descriptions, suggests that the TCLP may not adequately

detect situations that could result in harm to human health or the environment. The blame cannot unambiguously be

placed on the TCLP, however. Even if the TCLP accurately predicts TC leachate levels, site-specific fate and

transport processes (e.g., dilution by a factor of less than 100) and waste management practices could result in

the exceedances of MCLs and other regulatory levels.

10.2.3 Potential Gaps Associated with Non-TC Waste Constituents

Exhibit 10-3 summarizes the evaluation of potential gaps associated with non-TC chemicals that are known

or possible non-hazardous industrial waste constituents. Separate evaluations are presented for each of the 10

categories of chemicals identified in Chapter 4, which are associated with the groundwater, inhalation, or

indirect pathways:

Metals and other inorganics;

Volatile chlorinated organics;

Volatile hydrocarbons;

Other volatile organics;

Pesticides and related compounds;

Phthalate esters;

Phenolic compounds;

Polycyclic aromatic hydrocarbons;

Other semivolatile organic compounds; and

LNAPLs and DNAPLs.

Nature of Risk. A number of chemicals in some of the groups listed above are suspect carcinogens. Other

chemicals have the potential to cause reproductive and/or developmental effects in
Page 10-14

Exhibit 10-3

Evaluation of Potential Gaps Associated with Non-TC Chemicals

Chemical Type Nature of Risk trial Waste tions lion lbs. Affected Industries Methods Regulations Comments/Major Data Gaps

Presence in Non- Constituents in 1994 Reported

Hazardous Indus- Release Descrip- Releases> One Mil- Affected Management Potential Coverage by Other

a

Frequently Detected TRIChemicals with

GROUNDWATER PATHWAYS

Metals/Inorga- Potential cancer risks > 61 elements, com- Beryllium, man- Copper, zinc, Chemicals, refuse 78 percent of State Industrial D; Cali- Exposure at individual

nics 10 and noncancer risks of pounds, or families ganese, zinc, cop- manganese, cyanides, systems, paper have detections from fornia TC includes 10 addi- residential wells not -5

HQ>1 of compounds; most per, nickel, nickel, antimony about 66 percent of landfills; 15 per- tional metals; Michigan TC known

important are prob- cyanides detections in cent from surface includes copper and zinc; many

ably the metals, release descrip- impoundments; 5 have MCLs or SMCLs

beryllium, copper, tions; 10 other percent from land

manganese, nickel, industries have application units.

zinc, cyanides frequent detections

Volatile Potential cancer risks > 45 compounds Methylene chlo- Methylene Refuse systems, 79 percent of State Industrial D; most in Limited data on

Chlorinated 10 and noncancer risks of ride, ethylidene chloride, trichloro- paper, and chemicals detections from Appendix VIII; RCRA listings; wastestream and waste

Organics HQ>1 dichloride ethene, 1,1,1-tri- have about 85 percent landfills; 13 per- California TC includes 1,2- management practices

-5

 Many of these chemicals chloroethane, of detections cent from surface dibromo-3-chloropropane; manycontributing to

are suspect carcinogens. chloromethane, Freon impoundments. have MCLs, MCLGs groundwater releases

113

Volatile Potential cancer risks > 13 compounds Toluene, xylenes Toluene, xylenes, Chemicals, refuse 68 percent of State Industrial D; RCRA Petroleum hydrocarbons

Hydrocarbons 10 and noncancer risks of styrene, ethylbenz- systems, and paper detections from listings; all in Appendix exempt from RCRA -5

HQ>1. ene, cumene have 80 percent of landfills; 27 per- VIII; most have MCLs and/or Limited data on

detections cent from surface AWQCs wastestreams and manimpoundments. agement practices contributing most to

groundwater releases

Other Volatile Potential cancer risks > 58 compounds Acetone Methanol, methyl Chemicals, refuse 75 percent of State Industrial D; most in Wide range of toxicOrganics 10 and noncancer risks of ethyl ketone, systems, and paper detections from Appendix VIII; RCRA listings; ological, fate and trans- -5

HQ>1 methyl-isobutyl industries have 88 landfills and the California TC includes port properties 

 Highly variable toxicity ketone, n-butanol, percent of detec- remainder from acrylonitrile; few have MCLs, Limited data on

and fate and transport formaldehyde, aceto- tions surface impound- MCLGs wastestreams and manproperties nitrile, acetalde- ments. agement practices conhyde, acrylonitrile, tributing to groundwater

vinyl acetate, releases

propylene oxide

Phenolic Com- Potential noncancer 13 compounds Phenol Phenol; combined 10 industries with 56 percent of State Industrial D; all in Most compounds are of

pounds risks of HQ>1 cresols release detections; among detections at land- Appendix VIII relatively low toxicity,

exceeds one million the most widespread fills; 36 percent at biodegradable at low

pounds of constituent surface impound- concentrations

classes, despite low ments; and 8 percent Limited data on

number of detections at land application wastestreams

units.
Exhibit 10-3 (continued)

Evaluation of Potential Gaps Associated with Non-TC Chemicals

Chemical Type Nature of Risk trial Waste tions lion lbs. Affected Industries Methods Regulations Comments/Major Data Gaps

Presence in Non- Constituents in 1994 Reported

Hazardous Indus- Release Descrip- Releases> One Mil- Affected Management Potential Coverage by Other

a

Frequently Detected TRIChemicals with

Page 10-15

LNAPLs and Facilitated transport of 33 potential Potential 8 compounds plus LNAPLs/DNAPLs not No data. State Industrial D; RCRA Frequency of NAPL

DNAPLs organic chemicals from DNAPL formers, 13 LNAPL/DNAPL formers the phthalate esters reported in release Management prior- listings; some chemicals have problems in non-hazcontainment potential LNAPL were found in many (combined) descriptions ities are key to MCLs ardous waste appears to

 Long-lasting, difficult formers release descrip- DNAPL generation. be infrequent, espeto remediate reservoir of tions cially in recent years

groundwater contamination LNAPLs/ DNAPLs Limited wastestream

(DNAPL) were not reported and waste management data

as problem in any

release

descriptions,

possibly because of

limited reporting

requirements

Other Semi- Potential cancer risks > 67 compounds None Formic acid, acry- Chemicals industry Approximately State Industrial D; many in Highly variable toxivolatile Organic 10 and noncancer risks of lic acid, naph- has 45 percent of equal frequency in Appendix VIII; RCRA listings; cological, fate, and

Compounds HQ>1 thalene detections, landfills and sur- a few have MCLs; PCBs coveredtransport properties

-5

 Some are persistent remainder in five face impoundment by TSCA and some state Limited data on

and/or bioaccumulative. other industries releases hazardous waste regulations wastestreams and man-

 Highly variable fate and agement practices contransport properties tributing to groundwater

releases

INHALATION PATHWAYS

Volatile Chlo- Potential cancer risks > 45 compounds Methylene Methylene chlo- Refuse systems, 79 percent of State Industrial D; most in Limited data on

rinated Organics 10 and noncancer risks of chloride, ride, trichloroeth- paper, and chemi- detections from Appendix VIII; RCRA listings; wastestream and waste -5

HQ>1 ethylidene ene, 1,1,1-trichlo- cals, have about 85 landfills; 13 per- California TC includes 1,2- management practices

 Many of these chemicals dichloride roethane, chloro- percent of detec- cent from surface dibromo-3-chloropropane; contributing to air

are suspect carcinogens methane, Freon 113 tions impoundments majority are CAA HAPs; vinyl releases

chloride has NESHAP; many have

OSHA PELs

Volatile Potential noncancer 13 compounds Toluene, xylenes Toluene, xylenes, Chemicals, refuse 68 percent of State Industrial D; all in Petroleum hydrocarbons

Hydrocarbons risks of HQ>1 styrene, ethylbenz- systems, and paper detections from Appendix VIII RCRA listings; exempt from RCRA

 Benzene is the only ene, cumene have 80 percent of landfills; 27 per- all are CAA HAPs Limited data on

carcinogen detections cent from surface wastestreams and

impoundments management practices

contributing most to air

releases
Exhibit 10-3 (continued)

Evaluation of Potential Gaps Associated with Non-TC Chemicals

Chemical Type Nature of Risk trial Waste tions lion lbs. Affected Industries Methods Regulations Comments/Major Data Gaps

Presence in Non- Constituents in 1994 Reported

Hazardous Indus- Release Descrip- Releases> One Mil- Affected Management Potential Coverage by Other

a

Frequently Detected TRIChemicals with

Page 10-16

Other Volatile Potential cancer risks > 58 compounds Acetone Methanol, Chemicals refuse 75 percent of State Industrial D; most in Wide range of toxi-

<Organics 10 and noncancer risks of methylisobutyl systems, and paper detections from Appendix VIII; RCRA listings; cological, fate and -5

HQ>1 ketone, n-butanol, industries have 88 landfills and re- California TC includes transport properties 

 Highly variable toxicity formaldehyde, percent of detec- mainder from surface acrylonitrile; most are CAA Limited data on

and fate and transport acetinitrile, tions impoundments. HAPs; most have OSHA PELs wastestreams and

properties acetaldehyde, management practices

acrylonitrile, vinyl contributing to air

acetate, propylene releases

oxide

Pesticides and Potential cancer risks > 103 compounds None None Chemicals industry 87 percent of State Industrial D; RCRA Future generation is

Related Com- 10 and noncancer risks of has 80 percent of detections at sur- listings; most in Appendix unclear because of

pounds HQ>1 detections; refuse face impoundments; VIII; several are CAA HAPs; production and use

-5

 Some suspect endocrine systems have 10 remainder at land- FIFRA banned production or restrictions; potential

disruptors percent fills restricted use of many presence in remediation

 Possible reproductive waste may merit examining

toxicity and human devel- Limited data on

opment effects management practices

 Many are persistent and contributing to air

bioaccumulative. releases

Polycyclic Potential cancer risks > 19 compounds None (but PAHs None Relatively equally Relatively equally State Industrial D; many Highly variable

Aromatic 10 . are not mobile in frequent in frequent at have CAA HAPs; many have OSHAtoxicological, fate, and

Hydrocarbons Some are persistent and groundwater) detections from landfills and sur- PELs transport properties

-5

bioaccumulative. petroleum refining face impoundments Limited data on

and chemicals wastestreams and

industries; low management practices

frequency overall contributing to nongroundwater releases

Other Potential cancer risks > 67 compounds None Formic acid, Chemicals industry Approximately State Industrial D; many in Highly variable

Semivolatile 10 and noncancer risks of acrylic acid, has 45 percent of equal frequency in Appendix VIII; RCRA listings; toxicological, fate, and

Organic Com- HQ>1 naphthalene detections, remain- landfills and sur- many have OSHA PELs; some aretransport properties

pounds Some are persistent der in five other face impoundment CAA HAPs Limited data on

-5

and/or bioaccumulative. industries detections wastestreams and

 Highly variable fate and management practices

transport properties contributing to nongroundwater releases
Exhibit 10-3 (continued)

Evaluation of Potential Gaps Associated with Non-TC Chemicals

Chemical Type Nature of Risk trial Waste tions lion lbs. Affected Industries Methods Regulations Comments/Major Data Gaps

Presence in Non- Constituents in 1994 Reported

Hazardous Indus- Release Descrip- Releases> One Mil- Affected Management Potential Coverage by Other

a

Frequently Detected TRIChemicals with

Page 10-17

INDIRECT/FOOD-CHAIN PATHWAYS

Pesticides and Potential cancer risks > 103 compounds None None Chemicals industry 87 percent of State Industrial D; RCRA Future generation is

Related Com- 10 and noncancer risks of has 80 percent of detections at sur- listings; most in Appendix unclear because of

pounds HQ>1 detections; refuse face impoundments; VIII; several have AWQCs; production and use

-5

 Some suspect endocrine systems have 10 remainder at land- FIFRA banned production or restrictions; potential

disruptors. percent fills restricted use of many presence in remediation

 Possible reproductive waste may merit

toxicity and human devel- examining.

opment effects Limited data on

 Many are persistent and management practices

bioaccumulative. contributing to releases

Phthalate Esters Potential cancer risks > 6 compounds None None; combined Chemicals industry 54 percent of State Industrial D; di(2- High-volume chemicals

10 (one compound) phthalate ester has 70 percent of detections at sur- ethylhexyl)phthalate has MCL with high exposure -5

 Suspect endocrine releases exceed one detection; petroleum face impoundments and AWQC potential, but often low

disruptors million pounds, industry has 15 and 38 percent at toxicity

 Possible reproductive however percent landfills Limited understanding

toxicity, human develop- of dose-response

ment effects relationships,

 Several are persistent especially for endocrine

and bioaccumulative. disruption

Unclear significance of

exposures from nonhazardous waste relative

to other sources

Phenolic Com- Potential noncancer 13 compounds Phenol Phenol; combined 10 industries with 56 percent of State Industrial D; all in Most compounds are of

pounds risks of HQ>1 cresols release detections; among detections at land- Appendix VIII; several have relatively low toxicity,

exceeds one million the most widespread fills; 36 percent at AWQC biodegradable at low

pounds of constituent surface impound- concentrations

classes, despite low ments; 8 percent at Limited data on

number of detections land application wastestreams

units

Polycyclic Potential cancer risks > 19 compounds None (but PAHs None Relatively equally Relatively equally State Industrial D; most Highly variable

Aromatic 10 are not mobile in frequent in frequent at have CWA effluent limits; a toxicological, fate, and

Hydrocarbons Some are persistent, groundwater) detections from landfills and sur- few have AWQC; many are CAAtransport properties

-5

bioaccumulative. petroleum refining face impoundments HAPs Limited data on

and chemical wastestreams and

industries; low management practices

frequency overall contributing to nongroundwater releases
Exhibit 10-3 (continued)

Evaluation of Potential Gaps Associated with Non-TC Chemicals

Chemical Type Nature of Risk trial Waste tions lion lbs. Affected Industries Methods Regulations Comments/Major Data Gaps

Presence in Non- Constituents in 1994 Reported

Hazardous Indus- Release Descrip- Releases> One Mil- Affected Management Potential Coverage by Other

a

Frequently Detected TRIChemicals with

Page 10-18

Other Potential cancer risks > 67 compounds None Formic acid, Chemicals and Approximately State Industrial D; many in Highly variable

Semivolatile 10 and noncancer risks of acrylic acid, naph- allied products have equal frequency in Appendix VIII; RCRA listings; toxicological, fate, and

Organic Com- HQ>1 thalene 45 percent of landfills and sur- a few have AWQC transport properties

pounds Some are persistent and detections, face impoundment Limited data on

-5

bioaccumulative. remainder in five detections wastestreams and

 Highly variable fate and other industries management practices

transport properties contributing to nongroundwater releases

 Source: Exhibits 4-2 and 4-8. a
 Each chemical detected at a release site constitutes one detection. Thus, each release may have multiple detections (i.e., 2

multiple constituents) and each chemical may have multiple detections (i.e., be found at multiple releases).

Page 10-19

humans and ecological receptors. These and other indicators of hazard, combined with indicators of exposure

potential, demonstrate the potential for risks to human health or the environment.

Presence in Non-Hazardous Industrial Waste. The numbers of chemicals in the various classes that are

known or possible non-hazardous industrial waste constituents varies widely:

103 pesticides and related compounds,

67 other semi-volatile organic compounds,

61 metals or other inorganics,

58 other volatile organics,

45 volatile chlorinated organics;

46 NAPL formers (30 DNAPL formers and 9 NAPL formers),

19 polycyclic aromatic hydrocarbons,

13 volatile hydrocarbons,

13 phenolic compounds, and

6 phthalate esters.

Frequently Detected Constituents in Release Descriptions. Six non-TC metals are among the most

frequently occurring analytes in the release descriptions, along with three volatile chlorinated organics, one

other volatile organics, and one phenolic compound. The other classes of chemicals were not detected frequently

in the release descriptions, which predominately included groundwater contamination. The constituents found in

the release descriptions, however, frequently violated MCLs and other health-based levels.

TRI Chemicals with 1994 Reported Releases Exceeding One Million Pounds. These broad categories of

potential gaps include many chemicals with high TRI release volumes. In the case of the non-TC metals and other

inorganics, copper, zinc, manganese, and cyanides (as CNH) fell into this category. As was the case for the

frequency of occurrence in the release descriptions, several volatile organic waste constituents (chlorinated and

nonchlorinated) that have high TRI release volumes are TC analytes. None of the pesticides, phthalate esters, or

PAHs were among the chemicals with TRI releases greater than one million pounds. Two phenolic compounds and three

semivolatile organics were among the waste constituents with the highest TRI releases. Many of the potential NAPL

forming compounds also are high-release compounds.

Affected Industries. A relatively small number of industries tend to account for the bulk of the

occurrences of most categories of wastes with chemicals of concern. For almost all chemical classes, most

detections of chemicals constituents identified in the release descriptions were associated with three industry 2

groups: chemicals and allied products, refuse systems, and paper and allied products. Phenolic compounds diverge

from this pattern. The three industries identified above account for only about 35 percent of the releases of such

compounds, and 8 other industries had detections of phenolic constituents.

Affected Management Methods. As noted in Chapter 8, about 65 percent of the release descriptions were

associated with landfills, 28 percent with surface impoundments, and 11 percent from land application units, 4

percent from waste piles, with the other management units accounting for less than 1 percent each. (Several

release descriptions involved more than one facility.) This pattern generally applies to the individual classes

of chemicals, with a few significant exceptions. Since metals and inorganics were detected much more often than

other constituents, data on these detections dominate the overall pattern. The other classes of chemicals with

relatively high numbers of detections (volatile hydrocarbons, other volatile organics, phenolic compounds, and
Page 10-20

chlorinated volatile organics) were most commonly found in landfill releases, like the metals. For some chemical

classes with relatively low numbers of detections, such as other semivolatile organics, phthalate esters, and

PAHs, the proportions of detections from landfills and surface impoundments is almost equal, with few releases are

reported from other management units.

Potential Coverage by Other Regulations. As noted in Chapter 10, the chemicals associated with potential

gaps are subject to regulatory requirements that have some potential for controlling risks to human health and the

environment associated with nonhazardous industrial waste management. Since the bulk of these chemicals are

included in 40 CFR Part 261, Appendix VII, some wastes containing these chemicals are RCRA listed hazardous

wastes. Of course, other wastes with these constituents are not listed.

The design and operation of non-hazardous industrial waste management facilities managing all of the

various classes of waste constituents is largely under the control or potential control of state Industrial D

programs. All of these programs include a federally-mandated minimum set of design and monitoring requirements

for landfills. In some states, as discussed in Chapter 10, these minimum requirements have been expanded for

certain types of waste management units, wastes, and/or constituents. These requirements, however, vary

considerably from state to state. The appearance of various chemicals in groundwater at levels exceeding

regulatory standards suggests that the control of these chemicals under state Subtitle D programs may not afford

the intended level of protection nationwide.

The various chemical classes also are subject to medium-specific regulations under Safe Drinking Water

Act, Clean Air Act, and Clean Water Act. Most of the metals and commonly occurring inorganic and organic analytes

have MCLs established to protect drinking water quality. Many of the volatile chemicals are CAA Hazardous Air

Pollutants (HAPs). The effectiveness of this designation in protecting against exposures from waste management is

unclear, however, because the regulatory requirements apply only to facilities emitting more than 10 tons of HAPs

per year. Vinyl chloride is also controlled by a National Emission Standard for Hazardous Air Pollutants, which is

risk-based and protective to roughly the same risk level as the TC. Some of the pesticides, identified as being

among the most potentially hazardous waste constituents in Chapter 4, are already banned or strictly limited in

their use by FIFRA.

10.2.4 Potential Gaps Associated With Resource Damage and Large-Scale Environmental Problems

Chapter 5 briefly evaluated the following potential gaps in the hazardous waste characteristics related

to the following natural resource damages and large-scale environmental problems:

Natural Resource Damages

Groundwater pollution that may not present a health risk;

Odor problems;

Large-Scale Environmental Problems

Air deposition to the Great Waters;

Damages from airborne particulates;

Global climate change;

Potential damages from endocrine disruptors;

Red tides;

Stratospheric ozone depletion;

Tropospheric ozone and photochemical air pollution; and
Page 10-21

Water pollution.

At this time, the Agency does not plan to further consider any of these potential gaps, except possibly air

deposition and endocrine disruptions. These two potential gaps are discussed below and summarized in Exhibit 10-

4.

Air Deposition to the Great Waters

Few data are available on the contribution of non-hazardous industrial waste management to the deposition

of toxic particulates (including toxic metals and persistent chlorinated organic chemicals) in the Great Waters

ecosystems. While non-hazardous industrial waste constituents include toxic metals such as cadmium, lead, and

mercury, the extent of their long-range transport is unknown. Persistent chlorinated organic chemicals also are

among non-hazardous industrial waste constituents. Many of them have been banned from manufacture or further use

and therefore are unlikely to be managed in significant quantities as non-hazardous industrial wastes. They may,

however, continue to be found in remediation wastes.

Potential Damages from Endocrine Disruptors

The next potential gap is exposure to suspect endocrine disruptors. Depending upon what criteria are used

to identify these constituents, 28 suspect endocrine disruptors have been found among the TC analytes and known or

possible non-hazardous industrial waste constituents. Only the metals are encountered frequently in the release

descriptions, however. These metals are most commonly present in releases detected from facilities in the

chemicals and allied products, refuse systems, paper and allied products, industrial sand, and primary metals

industries. These releases are most often seen from landfills, followed by surface impoundments, based on the

release descriptions summarized in Chapter 2.

One suspect endocrine disruptor, styrene, is high on the TRI list, having total releases of 40 million

pounds in 1994. Almost all of the styrene releases are to air, with well under one million pounds being released to

land. Releases of the phthalate esters as a class also exceed one million pounds, although the releases of these

compounds individually are all less than one million pounds.

The use of many suspect endocrine disrupting pesticides has been banned or strictly limited. A

significant portion of the endocrine disruptors are TC analytes or otherwise listed in 40 CFR Part 261, Appendix

VIII. The greatest uncertainty concerning this potential gap is a lack of knowledge about dose-response

relationships for single and multiple agents, and the relative contribution of non-hazardous industrial waste

management to the total exposure of human and environmental receptors.
Page 10-22

Exhibit 10-4

Evaluation of Potential Gaps Associated With Certain Large-Scale Environmental Problems

Potential Gap Nature of Risk Waste Release Descriptions lbs. Affected Industries Methods Other Regulations Gaps

Presence in Non- Frequently Detected 1994 Reported

Hazardous Industrial Constituents in Releases > Million Affected Management Potential Coverage by Comments/Major Data

TRI Chemicals with

 Air Deposition to the Adverse ecological Many constituents, Lead, cadmium, Lead compounds Chlorinated organics Metals releases CAA Section 112(m) and Limited data on air

Great Waters effects on Great Lakes, such as pesticides, mercury are found in release predominantly from National Emissions deposition

Chesapeake Bay, Lake PCBs, dioxins, Pesticides were not descriptions from only a landfills and surface Standards for Hazardous contributions from

Champlain, and coastal cadmium, lead, and frequently detected. few industries and found impoundments Air Pollutants non-hazardous

water ecosystems mercury seldom therein Pesticide releases industrial waste

 Metals are found predominantly from management

frequently in release surface impoundments Uncertainty about

descriptions from many regional transport

industries patterns

 Potential Damage from Impaired 30 suspect endocrine Cadmium, lead, and Styrene, lead Most major generating 68 percent of RCRA listings, FIFRA, Limited waste stream

Endocrine Disruptors reproduction and disruptors mercury compounds industries detections in release SDWA, CWA and release data 

developmental Releases descriptions descriptions were from Dose-response data

disorders among humans found them in 12 landfills and 24 percent for exposure to single

and wildlife industries, with 70 from surface or multiple agents is

percent of the detections impoundments. lacking

in the chemicals, paper,

and sanitary services

industries.
Page 10-23

10.2.5 Gaps Associated with State TC Expansions and Listings

A number of states have expanded their hazardous waste program to regulate additional waste as hazardous. 

These state expansions include:

Adding constituents to the list of TC analytes. These additional constituents include

zinc, other metals, PCBs, pesticides, dioxins, and potential carcinogens.

Lowering existing TC regulatory levels. For example, California lowered the TC

regulatory level for pentachlorophenol from 100 mg/l to 1.7 mg/l.

Specifying alternative testing methods for identifying toxic hazardous waste. For

example, California requires use of the Wet Extraction Test (WET) in addition to the

TCLP. This test identifies several metal-containing wastes as hazardous that are

generally not identified as hazardous using the TCLP.

Using alternative approaches (other than listing constituents and regulatory levels) to

identify toxic hazardous wastes. For example, both California and Washington have

established toxicity criteria for wastes based on acute oral LD50, acute dermal LD50,

acute inhalation LC50, and acute aquatic 96-hour LC50 of the wastestreams taken as a

whole. A waste is designated hazardous if a representative sample of the waste meets any

of the acute toxicity criteria. In addition, California's regulations state that a

waste exhibits the characteristic of toxicity if the waste, based on representative

samples, "has shown through experience or testing to pose a hazard to human health or

environment because of its carcinogenicity, acute toxicity, chronic toxicity,

bioaccumulative properties or persistence in the environment."

Listing additional wastes as hazardous. The most common state-only listed wastes are

PCBs and waste oil. At least four states include additional "F" Wastes; three include

additional "K" wastes; five include additional "P" wastes; and six include additional

"U" wastes.

Restricting exemptions from the federal rules. Examples include chromium-bearing

wastes from leather tanning and finishing, various special wastes, certain arsenicaltreated wood wastes, petroleum contaminated media and debris that fail the TC, certain

injected groundwater, used CFC refrigerants that are reclaimed, and non-terne plated

used oil filters.

Thus, several states appear to be regulating a significant number of wastes as hazardous that are not covered under

federal RCRA regulations. These expansions reflect state judgments about gaps in the federal program and thereby

constitute potential gaps that may merit further investigation. State expansions have filled these gaps, but only

in the specific states with such expansions. Such potential gaps are possibly not being filled in the remaining

states that have not expanded the federal hazardous waste definitions.

10.2.6 Major Data Gaps and Uncertainties

The significance of potential gaps in the hazardous waste characteristics directly depends on the

magnitude of risks that are not addressed by the current characteristics or other programs. Thus, data gaps in the

Agency's ability to assess these risks are critical. 
Page 10-24

A key step in any risk analysis is characterizing the sources of releases of toxic or otherwise hazardous

materials to the environment. Thus, possibly the most important data gap is the lack of current data on the

generation, composition, and management of non-hazardous industrial wastes. EPA's most recent comprehensive data

on these topics are approximately a decade old. Many of the data are even older. While the basic nature of nonhazardous industrial wastes and waste management practices are not likely to have changed dramatically,

nonetheless, some important changes are likely to have occurred because of regulatory, economic, and technical

developments since the data were gathered.

Additional data gaps relate to exposure potential. Because of the lack of site-specific data, the Agency

had to rely primarily on proxies for exposure and risk potential. Environmental fate, transport, and

toxicological parameters have been used as a primary screening criteria to identify and evaluate hazards. As

noted in Chapter 5, consistent and reliable data related to these properties are available for only a relatively

limited portion of the universe of chemicals under consideration.

Likewise, the Agency has no direct data on the amounts of certain constituents released from nonhazardous industrial waste management units. Instead, 1994 TRI release data were used as proxies for such data. 

Another data source the Agency employed to assess exposure potential was the release descriptions from nonhazardous industrial waste management facilities. While these data provide direct evidence of environmental

contamination, it is often not clear whether the management practices that resulted in releases are still in use.

Some data gaps in this analysis are common to all risk analyses. For example, the need to conduct analysis

on a national scale and to consider a wide range of site conditions, facility characteristics, and geographic

settings dictates the use of generic, rather than site-specific modeling to estimate exposures through the various

pathways. Thus, the analysis of groundwater exposures relies on probabilistically-defined dilution and

attenuation values and the screening-level risk modeling uses highly generic release, transport, and exposure

models. This approach only roughly approximates potential risks to humans and ecological receptors. Moreover,

extensive professional judgment was required to generalize from generic modeling for specific chemicals to broad

classes of waste constituents.

Another major source of uncertainty is associated with toxicity of the waste constituents. The doseresponse models and data used are the most current available to the Agency. Nevertheless, substantial uncertainty

exists regarding the probability and severity of adverse effects as a function of dose for many chemicals. The use

of a generically defined "chronic" exposure period may mask important relationships between exposure periods and

effects. Also, the Agency was not able to derive any specific dose-response relationships for endocrine

disruptors or for any non-additive combinations of pollutant exposures. These uncertainties, unlike some of the

others just discussed, are not likely to be resolved in the near future.

10.3 Framework for Determining an Appropriate Course of Action

The U.S. Environmental Protection Agency will consider the appropriate course of action to address

significant gaps or potential gaps in the hazardous waste characteristics identified by the Study. This section

describes the framework that EPA plans to use in considering what course of action is appropriate. As part of this

process, the Agency will consider comments on the Study from interested parties.

EPA's approach for considering a course of action will include two main steps:

Step 1: Identify the critical research needs and associated next steps necessary to analyze key issues

and fill major data deficiencies identified in the Scoping Study; and
Page 10-25

Step 2: Identify and evaluate options to address the environmental management concerns resulting from

any gaps in the characteristics that were clearly identified in the Scoping Study.

Both of these steps are described in more detail below.

10.3.1 Step 1: Identify Critical Research Needs and Next Steps Necessary to Analyze Key Issues and Fill

Major Data Deficiencies

The results of the Scoping Study vary greatly in terms of the certainty that can be attributed to gaps in

the hazardous waste characteristics. Some of the potential gaps, most notably certain limitations in the ICR

characteristics, are clearly identifiable problems. Most potential gaps, however, are associated with

considerable uncertainty that limits the degree to which conclusions can be made about either the precise nature

and extent of the gap or how, if at all, it should be addressed. Thus, a critical activity in the near-term will be

to assess what additional data and analysis are needed to reduce uncertainty and better determine the significance

of the most important potential gaps in the characteristics identified by the Scoping Study.

10.3.2 Step 2: Identify and Evaluate Options to Address Any Clearly Identified Gaps

Some of the gaps identified in the Scoping Study are sufficiently defined that the Agency can consider

options for addressing the problem. Modifying an existing characteristic or developing a new characteristic may

be an appropriate method of filling some of these gaps. Other gaps may be better addressed through other

regulatory programs or in coordination with such programs. Thus, the list of options that the Agency may consider

include:

Specifying additional or revised test methods;

Expanding the definitions of existing characteristics;

Modifying the characteristics to reflect new risk data and modeling techniques;

Creating new characteristics, including contingent characteristics based on management method

or the type of generator or waste;

Identifying new hazardous waste listings or modifying existing listings;

Modifying other regulatory programs (e.g., Subtitle D);

Developing a non-regulatory approach (e.g., recycling, waste minimization); and

Promoting voluntary industry programs.

In evaluating a range of feasible options for particular gaps, the Agency will consider a variety of

factors including, but not necessarily limited to the following:

Affected industries, wastes, and management practices;

Human health and environmental benefits, such as reduced hazards and loadings of hazardous

constituents;
Page 10-26

Compliance costs and difficulties; and

Implementation and administration costs and difficulties.

Evaluating options can be a highly complex and data-intensive activity. Thus, the Agency may be unable to

determine quickly that a particular approach is appropriate. Nevertheless, analyzing options can help to narrow

the range of feasible and appropriate actions and help to identify the critical issues that need to be resolved in

selecting an approach.
Page 10-27

CHAPTER 10. SUMMARY EVALUATION OF NATURE AND

EXTENT OF POTENTIAL GAPS ........................ 10-1

10.1 Overview of the Evaluation of Potential Gaps ................................. 10-1

10.1.1 Objectives of the Gaps Analysis .................................... 10-1

10.1.2 Criteria Used for Evaluating Gaps ................................... 10-1

10.2 Findings of the Evaluation ................................................ 10-3

10.2.1 Potential Gaps Associated with the ICR Characteristics .................. 10-3

10.2.2 Potential Gaps Associated with TC Analytes .......................... 10-8

10.2.3 Potential Gaps Associated with Non-TC Waste Constituents ............. 10-14

10.2.4 Potential Gaps Associated With Resource Damage and Large-Scale Environmental

Problems ...................................................... 10-22

10.2.5 Gaps Associated with State TC Expansions and Listings ................ 10-25

10.2.6 Major Data Gaps and Uncertainties ................................. 10-26

10.3 Framework for Determining an Appropriate Course of Action ................... 10-27

10.3.1 Step 1: Identify Critical Research Needs and Next Steps Necessary to Analyze Key Issues

and Fill Major Data Deficiencies .......................................... 10-27

10.3.2 Step 2: Identify and Evaluate Options to Address Any Clearly Identified Gaps10-27
Page 10-28

Exhibit 10-1

Evaluation of Potential Gaps Associated With the Ignitability, Corrosivity, and Reactivity (ICR) Characteristics 10-4

Exhibit 10-2

Evaluation of Potential Gaps Associated with Toxicity Characteristic Analytes and TCLP ........... 10-9

Exhibit 10-3

Evaluation of Potential Gaps Associated with Non-TC Chemicals ............................. 10-15

Exhibit 10-4

Evaluation of Potential Gaps Associated With Certain Large-Scale Environmental Problems ........ 10-24